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Binding porphyrins to the simplest models for membranes (surfactants micelles) has attracted much interest due to the possibility of understanding these biological processes. Micelles, microemulsions and vesicles constitute a very active... more
Binding porphyrins to the simplest models for membranes (surfactants micelles) has attracted much interest due to the possibility of understanding these biological processes. Micelles, microemulsions and vesicles constitute a very active area of investigation for the manifold implications in chemistry, physics, biology and materials sciences [1]. In supramolecular chemistry, such organized noncovalent assemblies have been exploited to mimic membrane behavior [2,3], taking advantage of their propensity to entrap or compartmentalize different species, leading in some cases to a high degree of organization and, to create gradients of concentration. Micelle with charged surfaces bind counterions selectively, and their solution properties are sensitive to the type of conuterion and theirs concentration. Recently, several studies have been made on the micellar behavior of cationic surfactant systems with different bulky head groups, and these systems exhibited head group induced structura...
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The anisotropic silver nano-particles were synthesized by using a simple, efficient and eco-friendly method in the presence of Taxus baccata extract as reducing and stabilizing agent. The colloidal monodispersed nanoparticles were... more
The anisotropic silver nano-particles were synthesized by using a simple, efficient and eco-friendly method in the presence of Taxus baccata extract as reducing and stabilizing agent. The colloidal monodispersed nanoparticles were characterized by different methods including UV-Vis spectroscopy, SEM, TEM, AFM, EDS, FTIR, TGA, DLS and Zetasizer. Following the investigation of anticancer activity of the nanoparticles on MCF-7, Caov-4 and HeLa cancer cell lines using MTT assay, its mechanism was further investigated using flow cytometry and real-time PCR.
High-quality colloidal silver nanoparticles (AgNP) were synthesised via a green approach by using hydroalcoholic extracts of . Silver nitrate was used as a substrate ion while the plant extract successfully played the role of reducing and... more
High-quality colloidal silver nanoparticles (AgNP) were synthesised via a green approach by using hydroalcoholic extracts of . Silver nitrate was used as a substrate ion while the plant extract successfully played the role of reducing and stabilising agents. The synthesised nanoparticles were carefully characterised by using transmission electron microscopy, atomic-force microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and UV-vis spectroscopy. The maximum absorption wavelengths of the colloidal solutions synthesised using 70 and 96% ethanol and 100% methanol, as extraction solvents, were 430, 485 and 504 nm, respectively. Interestingly, the size distribution of nanoparticles depended on the used solvent. The best particle size distribution belonged to the nanoparticles synthesised by 70% ethanol extract, which was 20-40 nm. The antibacterial activity of the synthesised nanoparticles was studied on , and using disk diffusion, minimum inhibitory concentrations and minimum bactericidal concentrations assays. The best antibacterial activity obtained for the AgNPs produced by using 96% ethanolic extract.
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Porphyrins and their metal derivatives are strong DNA binders with association constant of 104 to 105 M 1 . Some of these compounds have been used for radiations sensitization therapy of cancer and are targeted to interact with cellular... more
Porphyrins and their metal derivatives are strong DNA binders with association constant of 104 to 105 M 1 . Some of these compounds have been used for radiations sensitization therapy of cancer and are targeted to interact with cellular DNA. Binding of porphyrins to DNA changes the spectral and other physico chemical characteristics of porphyrins. The mode of binding can be extracted from inspection of spectral changes of porphyrin. Hence, Uv-Vis spectroscopy is one of the most usual techniques for such investigations. More over, measuring of these spectral changes at various molar ratio of DNA/porphyrin can let to calculate the binding constant and stoichiometry. In the present work , the interaction of three water soluble porphyrins, tetra (ptrimethyle) ammonium phenyl porphyrin iodide (TAPP) as a cationic prophyrin , tetra sodium meso— tetrakis (p— sulphonato phenyl) porphyrin (TSPP) as an anionic porphyrin and manganese tetrakis (p— sulphonato phenyl) porphyinato acetate (MnTSPP...
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Selective isolation of HLA-G+ cells from HLA-G− cells with MEM-G/9-MNPs. It is an efficient tool for the isolation of fetal cells from the endocervical sample for prenatal screening.
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Curcumin (CUR) is the active curcuminoid with many physiological, biochemical, and pharmacological properties. Solubility and stability of CUR is the limiting factors for realizing its therapeutic potential. Bovine β-casein is an abundant... more
Curcumin (CUR) is the active curcuminoid with many physiological, biochemical, and pharmacological properties. Solubility and stability of CUR is the limiting factors for realizing its therapeutic potential. Bovine β-casein is an abundant milk protein that is highly amphiphilic and self-assembles into stable micellar nanoparticles in aqueous solution. β-Casein nanoparticle can solubilize CUR molecules. In the present study, we introduced a drug-delivery system comprising hydrophobic anticancer drug, CUR, entrapped within β-casein-based nanoparticles. The interaction of CUR with β-casein was investigated using steady-state fluorescence spectroscopy and molecular docking calculation. Results showed that at pH 7, CUR molecules bind to β-casein micelle and formed complexes through hydrophobic interactions. Forster energy transfer measurements and molecular docking studies suggested that CUR molecules bind to the hydrophobic core of βcasein. The binding parameters including number of sub...
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Interactions of 5, 10, 15, 20-tetrakis (N-benzylpyridilium-4-yl) porphyrin (TBzPyP) and its metal complexes (Cu(II), Ni(II), Co(II) and Mn(III)) with calf thymus DNA were investigated in view of thermodynamics; using UV-vis spectroscopy.... more
Interactions of 5, 10, 15, 20-tetrakis (N-benzylpyridilium-4-yl) porphyrin (TBzPyP) and its metal complexes (Cu(II), Ni(II), Co(II) and Mn(III)) with calf thymus DNA were investigated in view of thermodynamics; using UV-vis spectroscopy. The measurements were done in 5 mM phosphate buffer, pH 7.0. The optical absorption spectra of porphyrins were analyzed in order to obtain binding constants and stoichiometries using SQUAD software. The results show that the best fitting corresponds to 1:1 complex model between base pair of DNA and porphyrins. Running the measurements at various temperatures provided the completed thermodynamic analysis on basis of van't Hoff equation. The results represents the enthalpy driven of the process and the predominate role of electrostatic interaction. The following order has been obtained for binding affinity and exothermicity: MnTBzPyP > CoTBzPyP > NiTBzPyP > CuTBzPyP > TBzPyP This result has been interpreted on basis of the chemical str...
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Aggregation behavior of water soluble porphyrins, 5-(1-(4-carboxybutyl) pyridinum-4-yl) 10,15,20-tris (1-methylpyridinium4-yl) porphyrin (5-CBPyP) in the presence of various concentrations of calf thymus DNA (ct-DNA) and sodium chloride... more
Aggregation behavior of water soluble porphyrins, 5-(1-(4-carboxybutyl) pyridinum-4-yl) 10,15,20-tris (1-methylpyridinium4-yl) porphyrin (5-CBPyP) in the presence of various concentrations of calf thymus DNA (ct-DNA) and sodium chloride were studied in comparison with meso-tetrakis (4-N-methyl pyridinum) porphyrin (TMPyP), by optical absorption, fluorescence and resonance light scattering (RLS) spectroscopies. Both porphyrins obey Beer’s law in extended range of concentration. Optical absorption and RLS measurements demonstrated nonaggregation for both porphyrins under increasing concentration of ct-DNA and NaCl. However, in comparison, 5-CBPyP had less t ndency for aggregation that may be taken as an advantage for its probable application in photodynamic therapy of cancer. The trend of changes in absorption spectra of both porphyrins in the presence of ct-DNA indicates the homogeneous intercalation binding mode. The values of (2.81 ± 0.28) × 10 M and (0.95 ± 0.09) × 10 M were obtai...
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Because of participation in many aspects of human life, and due to oxidation-sensitive characteristics of dopamine (DA) and arachidonoyl dopamine (AA-DA), the necessity of biocompatible carrier to keep them against oxidation is of... more
Because of participation in many aspects of human life, and due to oxidation-sensitive characteristics of dopamine (DA) and arachidonoyl dopamine (AA-DA), the necessity of biocompatible carrier to keep them against oxidation is of importance. In this work, we explored the putative binding sites of DA and AA-DA to -lactoglobulin (BLG) as potent carrier. Docking results identified the binding sites, involved residues and driving forces to the binding process of these ligands. The dissimilar binding site of AA-DA in comparison with DA has been designated by different values of Gibbs free energy, biding constants and contact residues. Molecular dynamics simulation outcomes confirmed that both compounds stayed in their predicted binding sites during the entire time of simulation with no major secondary and tertiary protein structural changes which pointed that BLG might be considered as a suitable oxidation-protective carrier for these compounds.
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This paper is designed to examine the binding behavior of Coumarin with bovine -casein (βCN) through fluorescence spectroscopy and molecular modeling techniques. The data analysis on fluorescence titration experiments at various... more
This paper is designed to examine the binding behavior of Coumarin with bovine -casein (βCN) through fluorescence spectroscopy and molecular modeling techniques. The data analysis on fluorescence titration experiments at various temperatures represents the enthalpy driven nature for the formation of Coumarin–βCN complex and the prevailed role of hydrogen bonds and van der Waals interactions in the binding process. The results also represent the static quenching of tryptophan and dynamics quenching of tyrosine and phenylalanine residues due to the binding of Coumarin. It can be concluded from molecular docking studies that Coumarin binds to several polar and non-polar residues in the hydrophobic core of βCN with the binding energy of -6.96 kcal mol-1. Finally, analysis of molecular dynamics (MD) simulation results suggested that the interactions between βCN and Coumarin are very stable and the binding of Coumarin restricted the flexibility of important residues in the binding site o...
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In order to shed more light on the effect of peripheral groups of porphyrin core intophysicochemical properties and DNA binding behavior of porphyrins, we have chosen toinvestigate solution properties and calf thymus DNA binding behavior... more
In order to shed more light on the effect of peripheral groups of porphyrin core intophysicochemical properties and DNA binding behavior of porphyrins, we have chosen toinvestigate solution properties and calf thymus DNA binding behavior of meso-tetrakis (4-Nbenzyl-pyridyl) porphyrin (TBZPyP) and its Mn (III), Co (III), Ni (II) and Cu (II) complexesderivatives have been studied in thermodynamic viewpoint using Uv/Vis spectroscopy. They havebeen chosen because of their good solubility in physiological solution as well as moderatelyhydrophobic property, so that we may consider them as promising compounds for clinicalapplications. The measurements were done in 1mM phosphate buffer, pH 7.0 and varioustemperatures. The optical absorption spectra of porphyrins were analyzed in order to obtainbinding constants and stoichiometries using SQUAD software. The results show that the bestfitting corresponds to a 1:1 complex model between base pair of DNA and porphyrins. Theestimation of binding c...
Isothermal titration calorimetry (ITC) was utilized at conditions close to physiological (50 mM HEPES buffer, pH 7.4 and 160 mM NaCl) and at various temperatures of 25, 30, 35 and 40 °C to evaluate the thermodynamic parameters, enthalpy... more
Isothermal titration calorimetry (ITC) was utilized at conditions close to physiological (50 mM HEPES buffer, pH 7.4 and 160 mM NaCl) and at various temperatures of 25, 30, 35 and 40 °C to evaluate the thermodynamic parameters, enthalpy and heat capacity changes, and subsequently the unfolding process of apo-human serum tarnsferrin (apo-hTf) in the presence of cetylpyridinium chloride (CPC) as a cationic surfactant. The precise thermograms and heat capacity curves obtained and interpreted in terms of molecular events such as specific and non-specific binding and the unfolding process. The analysis of obtained enthalpograms and heat capacity changes profile showed a distinct extreme region close to [CPC]/[apo-hTf] mole ratio of 20 indicated that predominant cooperative unfolding occurs at this mole ratio via a two states mechanism.
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Synthesis and antiproliferative activities of Cu(ii) complexes with tridentate Schiff-base ligands containing pyridine and 3,5-halogen substituted phenol moieties were investigated.
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Abstract Recently, membrane-immobilized enzyme as an affordable bioreactor has been explored in various fields such as biodiesel production and biosensing because of the reusability of the biocatalyst, increasing its stability and being a... more
Abstract Recently, membrane-immobilized enzyme as an affordable bioreactor has been explored in various fields such as biodiesel production and biosensing because of the reusability of the biocatalyst, increasing its stability and being a low-cost separating unit for producing pure products. Usually, membrane modification could affect the surface morphology and hydrophilicity to make them appropriate for enzyme immobilization. In this context, the modified nanocomposite membranes of polyethersulfone (PES) with various percentages (x: 0.00, 0.25, 0.50, 1.00, 2.00, 3.00) of the graphene oxide nanosheets (GON) named (PGx) are synthesized through the phase inversion technique. The enzymatic hybrid membrane reactors (EHMRs) are provided through the Candida rugosa lipase (CRL) immobilization on the synthesized hybrid membranes. The structure and surface functionalities of the synthesized GON and hybrid membrane are characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and attenuated total reflection (ATR), respectively. The effect of the GON incorporation and CRL immobilization on the morphology of the membrane are explored through field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), contact angle goniometry, and surface free energy analysis. After measuring the porosity of the hybrid membranes with different amounts of GON, their performance, before and after CRL immobilization, are studied through pure water flux. The effective parameters on the activity and performance of EHMR such as GON percentages, CRL initial concentration, immobilization time, and storage condition are accurately optimized. The examination of the relative activity, reusability, and product permeability display that EHMR with 1.00% of GON (EHMR1) is the most efficient between EHMRs with different percentages of GON. Moreover, EHMR1 exhibits the enhancement in pH and thermal stability compared with free CRL and even the immobilized CRL on GON. While the storage stability of the wet- EHMR1 is higher than that of the dry-EHMR1, the stored wet- EHMR1 at 4 °C is more stable than room temperature. Because of these advantages, it is recommended that this bioactive membrane could be a passable candidate for application in the environmental, analytical, and industrial processes.
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Density (ρ), viscosity (η) and surface tension (γ) of three amino acids (valine, alanine, and glycine) have been measured at a different mass fraction (0.002 - 0.009) of aqueous hydroxypropyl-β-cyclodextrin (HPβCD) mixtures and different... more
Density (ρ), viscosity (η) and surface tension (γ) of three amino acids (valine, alanine, and glycine) have been measured at a different mass fraction (0.002 - 0.009) of aqueous hydroxypropyl-β-cyclodextrin (HPβCD) mixtures and different temperatures (278.15 - 295.15 K). The formation of inclusion complexes has been analyzed via evaluating the amounts of apparent and limiting apparent molar volumes, limiting apparent molar expansibilities, activation energy, kinematic, relative, intrinsic, spatial, and dynamic viscosities. The surface tension studies indicated that the inclusion complexes have been formed with 1:1 stoichiometry and mediated by hydrophobic effects and electrostatic forces. Additionally, the ρ and η parameters were evaluated by molecular modeling experiments to provide more details on the mechanisms of the complexation.
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ABSTRACT In the present study, enzymatic biodiesel production from low-cost, non-edible crude Eruca sativa oil was investigated. Candida rugosa lipase (CRL), a commercially promising biocatalyst in different industries, was used. Although... more
ABSTRACT In the present study, enzymatic biodiesel production from low-cost, non-edible crude Eruca sativa oil was investigated. Candida rugosa lipase (CRL), a commercially promising biocatalyst in different industries, was used. Although this source of lipase has been reported as unsuitable for biodiesel production from non-edible oil, in this study, it was attempted to use this enzyme for production of fatty acid methyl esters (FAME) from Eruca sativa oil in a solvent-free system. For the first time, the effects of pre-hydrolysis and pH on the yield of biodiesel were evaluated. Afterward, the four most commonly reported influential parameters were analyzed with the use of response surface methodology (RSM). It was observed that pre-hydrolysis had a significant effect on biodiesel conversion due to the mechanism of enzymatic biodiesel production. Deionized water was more efficient in comparison with phosphate buffer with different pH values. According to the RSM analysis, water content and temperature have a highly significant effect on biodiesel production. Methanol-to-oil ratio and enzyme amounts were also significant factors in FAME production. The optimum methanol-to-oil ratio, enzyme amount, water content, and temperature for achieving high conversion was found to be 3:1, 5 mg, 40%, and 21 °C, respectively.
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Abstract Membrane-immobilized enzymes have received increasing attention in a variety of fields such as biosensors, enzymatic reactors, and membrane bioreactors. In this study, Candida rugosa lipase (CRL) was covalently immobilized on... more
Abstract Membrane-immobilized enzymes have received increasing attention in a variety of fields such as biosensors, enzymatic reactors, and membrane bioreactors. In this study, Candida rugosa lipase (CRL) was covalently immobilized on nanocomposite membrane. Initially, the Fe3O4@SiO2 nano-particles were dip-coated onto the ultrafiltration membrane surface through a low temperature hydrothermal (LTH) process, and then, reacted with 3-aminopropyletriethoxysilane (APTS). Glutaraldehyde was used as a coupling agent to covalently immobilize lipase on the nanocomposite membrane surface. Various techniques such as SEM, TEM, XRD, FTIR, AFM, contact angle goniometry and surface free energy measurement were applied to characterize the nanocomposite membrane. The results showed that the immobilization process was successful in terms of enzyme activity and immobilization efficiency. It was found that the activated nanocomposite membrane greatly improved the relative activity and loading capacity in comparison to unmodified UF membrane. The investigation of kinetic parameters of enzymatic reaction shows the decreasing of Km and vmax due to immobilization which represents the increasing of substrate affinity and decreasing of catalytic activity of immobilized enzyme. The higher thermal, storage, and operational stability of immobilized enzyme make it a suitable candidate for to bio-catalytic processes.
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High quality colloidal gold nanoparticles with promising anticancer activity were synthesized using Taxus baccata extracts.
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Abstract A facile and novel semi-biosynthesis method was reported to develop multifunctional magnetic-plasmonic nanostructures with potent and specific anticancer activity. Silver and gold nanoseeds were synthesized in the presence of... more
Abstract A facile and novel semi-biosynthesis method was reported to develop multifunctional magnetic-plasmonic nanostructures with potent and specific anticancer activity. Silver and gold nanoseeds were synthesized in the presence of Taxus baccata extracted Taxanes, as reducing and capping agents, and used to decorate the silica coated iron oxide nanoparticles. The resulted nanostructures were characterized using UV–Vis spectroscopy, FE-SEM, TEM, FTIR, EDS, and DLS. The resulted hollow and porous nanostructures displayed semi-spherical shapes and sizes between 200 and 500 nm with appropriate magnetic and plasmonic properties. FTIR analysis showed efficient encapsulation of nanostructures by the organic compounds which led to their appropriate colloidal stability. MTT assay and microscopic studies revealed potent and specific anticancer activity of silver decorated magnetic nanostructures (FeAg-Ns), so that after 48 h incubation of human cervical (HeLa) and breast (MCF-7) cancer cells with 100 μg mL− 1 FeAg-Ns up to 70.4 ± 2.02 and 98.6 ± 2.36% mortality were obtained, respectively. Moreover, the nanostructures displayed significantly less cytotoxicity (up to 40.5 ± 1.82%) on noncancerous human fibroblast cells. In conclusion, the synthesized nanostructures have great potential to develop theranostic agents for bio-imaging and magnetically targeted cancer therapy.
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Novel methods have been developed for lipase immobilization on poly acrylonitrile (PAN) membranes to increase the activity and stability of the immobilized lipase.
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In this work, the terbium(III), dysprosium(III), and ytterbium(III) complexes containing 2, 2'-bipyridine (bpy) ligand have been synthesized and characterized using CHN elemental analysis, FT-IR, UV-Vis and H-NMR techniques and their... more
In this work, the terbium(III), dysprosium(III), and ytterbium(III) complexes containing 2, 2'-bipyridine (bpy) ligand have been synthesized and characterized using CHN elemental analysis, FT-IR, UV-Vis and H-NMR techniques and their binding behavior with human serum albumin (HSA) was studied by UV-Vis, fluorescence and molecular docking examinations. The experimental data indicated that all three lanthanide complexes have high binding affinity to HSA with effective quenching of HSA fluorescence via static mechanism. The binding parameters, the type of interaction, the value of resonance energy transfer, and the binding distance between complexes and HSA were estimated from the analysis of fluorescence measurements and Förster theory. The thermodynamic parameters suggested that van der Waals interactions and hydrogen bonds play an important role in the binding mechanism. While, the energy transfer from HSA molecules to all these complexes occurs with high probability, the order ...
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A comprehensive study was conducted toward the green and facile synthesis of biocompatible magnetite nanoparticles for the efficient removal of organic contaminants from water. The nanoparticles were synthesized using a modified... more
A comprehensive study was conducted toward the green and facile synthesis of biocompatible magnetite nanoparticles for the efficient removal of organic contaminants from water. The nanoparticles were synthesized using a modified co-precipitation method and functionalized by the taxane diterpenoids extracted from Taxus baccata L., and fully characterized using UV-vis spectroscopy, SEM, FTIR, VSM, and XRD. The synthesized monodisperse magnetite nanoparticles, with a narrow size distribution of less than 50 nm, displayed significant and stable magnetic activity without surface oxidation after several months. The batch experiments clearly indicated the efficient iron-catalyzed removal of Nile blue, methylene blue, methylene orange, and 4-nitrophenol for several cycles without significant loss of catalytic activity. The relevant kinetic data of the dyes removal reactions were fitted to a pseudo-first order model. Moreover, in vitro MTT assay revealed high biocompatibility of the nanoparticles with no significant toxicity on different human cell lines. The overall results indicated high potential of green synthesized, biocompatible magnetite nanoparticles for the environmental applications especially wastewater remediation.
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In the present manuscript, a closed bipolar electrode system integrated with electrochemiluminescence (ECL) detection has been introduced for sensitive diagnosis of human breast cancer cells (MCF-7). For sensitive and selective detection,... more
In the present manuscript, a closed bipolar electrode system integrated with electrochemiluminescence (ECL) detection has been introduced for sensitive diagnosis of human breast cancer cells (MCF-7). For sensitive and selective detection, the anodic pole of the bipolar electrode was modified with the AS1411 aptamer, a specific aptamer for the nucleolin, and treated by the secondary aptamer modified gold nanoparticles. The electrochemiluminescence of luminol was followed in the presence of hydrogen peroxide on the anode pole of bipolar electrode (BPE) as an analytical signal. Moreover, 3D printed microchannels were used for the fabrication of BPE systems to minimize the required amounts of sample. The present aptasensor offers low cost, sensitive and selective cancer cell detection with two acceptable linear ranges. The first linear section appears within 10-100 cells and the latter is found to be within 100-700 cells. The limit of detection was about 10 cells.
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Chemotherapy constitutes the main strategy in management of breast cancer (BC). Lack of specificity and high burden of adverse effects of chemotherapeutic agents remain the most important impediments to successful treatment of BC... more
Chemotherapy constitutes the main strategy in management of breast cancer (BC). Lack of specificity and high burden of adverse effects of chemotherapeutic agents remain the most important impediments to successful treatment of BC patients. Folate receptor α (FRα) could be very promising for therapeutic targeting in this type of cancer. In this study, ß-lactoglobulin nanoparticles (BNPs) conjugated with folic acid and loaded with doxorubicin (FDBNPs) were prepared. Various characterization techniques were applied to determine the size, polydispersity and doxorubicin loading of prepared FDBNPs in comparison with doxorubicin-loaded BNPs (DBNPs). The results showed that FDBNPs are 109.77 ± 2.80 nm in diameter with well dispersed and spherical shapes. The biodegradation of FDBNPs in the presence of trypsin enzyme and in PBS at different pH (4 and 7) was spectrophotometrically monitored and the results showed that the FDBNPs with encapsulation efficiency of 68.82%±1.76% could deliver doxorubicin at clinically relevant doses. Effects of DBNPs and FDBNPs against MCF-7 and MDA-MB-231, BC and triple negative BC (TNBC) cell lines, respectively, showed significant inhibition of cell proliferation as well as induction of apoptosis. Based on these findings, FDBNPs with facilitated drug release and targeted doxorubicin delivery capacities could have high therapeutic potential for BC and TNBC.
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In this study, Rh2-treated graphene oxide (GO-Rh2), lysine-treated highly porous graphene (Gr-Lys), arginine-treated Gr (Gr-Arg), Rh2-treated Gr-Lys (Gr-Lys-Rh2) and Rh2-treated Gr-Arg (Gr-Arg-Rh2) were synthesized. MTT assay was used for... more
In this study, Rh2-treated graphene oxide (GO-Rh2), lysine-treated highly porous graphene (Gr-Lys), arginine-treated Gr (Gr-Arg), Rh2-treated Gr-Lys (Gr-Lys-Rh2) and Rh2-treated Gr-Arg (Gr-Arg-Rh2) were synthesized. MTT assay was used for evaluation of cytotoxicity of samples on ovarian cancer (OVCAR3), breast cancer (MDA-MB), Human melanoma (A375) and human mesenchymal stem cells (MSCs) cell lines. The percentage of apoptotic cells was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay. The hemolysis and blood coagulation activity of nanostructures were performed. Interestingly, Gr-Arg, Gr-Lys, Gr-Arg-Rh, and Gr-Lys-Rhwere more active against cancer cell lines in comparison with their cytotoxic activity against normal cell lines (MSCs) with ICvalues higher than 100 μg/ml. The results of TUNEL assay indicates a significant increase in the rates of TUNEL positive cells by increasing the concentrations of nanomaterials. Results were also ...
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In this study, we have reported the synthesis of graphene oxide nanosheets (GON) and its functionalization with 2, 4, 6-trichloro-1, 3, 5-triazine (TCT) through two routes, (a) directly reaction of GON with TCT (GON-1), and (b) reaction... more
In this study, we have reported the synthesis of graphene oxide nanosheets (GON) and its functionalization with 2, 4, 6-trichloro-1, 3, 5-triazine (TCT) through two routes, (a) directly reaction of GON with TCT (GON-1), and (b) reaction of GON with pre-functionalized TCT with 3-aminopropyltriethoxysilane (APTS) (GON-2). Subsequently, GON, GON-1 and GON-2 have been used as supports for immobilization of Candida rugosa lipase (CRL). Several techniques such as XRD, SEM, EDS, UV-Vis, CHNS, FTIR and AFM were applied to characterize the nano-structures and success of synthesis, functionalization and CRL immobilization processes. The results corresponding to optimization of immobilization process revealed the following order for values of loading capacity, immobilization yield and leaching of CRL: GON > GON-1 > GON-2, while this order is reversed for, specific activity and recovery activity. The assessment of operational parameters represents the high storage stability and reasonable...
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Traditional spherical albumin nanoparticles remain as the dominant shape of nano-carriers described in the literature at present, due to their simple desolvation method of synthesis. However, non-spherical shapes also show great promise... more
Traditional spherical albumin nanoparticles remain as the dominant shape of nano-carriers described in the literature at present, due to their simple desolvation method of synthesis. However, non-spherical shapes also show great promise as cancer drug delivery vectors. In this study, we report a novel synthetic strategy based on dimethyl sulfoxide (DMSO) addition during desolvation step, to produce doughnut-shaped bovine serum albumin nanoparticles (DBSA-NPs), while maintaining narrow size distributions and homogeneity. The characteristics such as size, polydispersity and doxorubicin loading of prepared DBSA-NPs in comparison with spherical ones were determined. The biodegradation of DBSA-NPs loaded with doxorubicin (Dox-DBSA-NPs) in the presence of trypsin enzyme was spectrophotometrically monitored directly based on doxorubicin release profile. The release profile was analyzed with different kinetic models and it was best fitted with Higuchi kinetics model. The anticancer effect o...
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In order to utilize the advantages of immobilization such as improvement of stability, increasing the catalytic activity, ability to recovery and reuse of enzyme from reaction medium, xylanase enzyme was immobilized on superparamagnetic... more
In order to utilize the advantages of immobilization such as improvement of stability, increasing the catalytic activity, ability to recovery and reuse of enzyme from reaction medium, xylanase enzyme was immobilized on superparamagnetic garphene oxide nanosheets (GOMNP). Xylanase, as a hydrolytic enzyme of xylan has widely used in industry. Since the xylan is bulk, for enhance accessibility of active sites of the immobilized xylanase, polyethylene glycol bis amine (PEGA) was used as a spacer for functionalization of GOMNP. The modified GOMNP and immobilized xylanase on PEGA-GOMNP (PEGA-GOMNP/Xy) were characterized through different analysis tools. The results showed that xylanase was attached to the functionalized nanocomposite with a yield of 273mg enzyme per gram PEGA-GOMNP. Thermal stability, pH stability, reusability and storage stability were determined for immobilized enzyme. The free and immobilized xylanase displayed an optimal enzymatic activity at 60°C and pH 6.5 and 7.5, respectively. The immobilized enzyme retained about 40% of the initial activity after 8 cycles with xylan substrate at 60°C. Also immobilized and free enzymes retained 35% and 20% of the initial catalytic activity after 90days storage at 4°C, respectively. Consequently, PEGA- modified GOMNP can be introduced as a biodegradable and suitable support for bioengineering.
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UV-Vis absorption data of β-lactoglobulin (BLG) and arachidonoyl serotonin (AA-5HT) in BLG complex were examined and analyzed using chemometrics method. Analysis of the spectral data matrices by using the multivariate curve... more
UV-Vis absorption data of β-lactoglobulin (BLG) and arachidonoyl serotonin (AA-5HT) in BLG complex were examined and analyzed using chemometrics method. Analysis of the spectral data matrices by using the multivariate curve resolution-alternating least squares (MCR-ALS) algorithm resulted to the pure concentration calculation and spectral profiles resolution of the chemical constituents and the values of (6.433±0.019)×10(4)M(-1), (4.532±0.007)×10(4)M(-1), (3.364±0.010)×10(4)M(-1) and (2.977±0.013)×10(4)M(-1) as estimated equilibrium constants at 288, 293, 298 and 303K, respectively. The number of chemical constituents involved in the interaction which was extracted by PCA method were free and bound BLG. The spontaneity of the binding process and critical role of hydrogen bonding and van der Waals interactions in stabilizing protein-ligand complex have been designated by negative values of Gibbs free energy, entropy and enthalpy changes. Molecular docking study showed that AA-5HT bin...
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A simple and eco-friendly method for efficient synthesis of stable colloidal silver nanoparticles (AgNPs) using Mentha pulegium extracts is described. A series of reactions was conducted using different types and concentrations of plant... more
A simple and eco-friendly method for efficient synthesis of stable colloidal silver nanoparticles (AgNPs) using Mentha pulegium extracts is described. A series of reactions was conducted using different types and concentrations of plant extract as well as metal ions to optimize the reaction conditions. AgNPs were characterized by using UV-vis spectroscopy, transmission electron microscopy, atomic force microscopy, dynamic light scattering, zetasizer, energy-dispersive X-ray spectroscopy (EDAX) and Fourier transform infrared spectroscopy (FTIR). At the optimized conditions, plate shaped AgNPs with zeta potential value of -15.7 and plasmon absorption maximum at 450 nm were obtained using high concentration of aqueous extract. Efficient adsorption of organic compounds on the nanoparticles was confirmed by FTIR and EDAX. The biogenic AgNPs displayed promising antibacterial activity on Escherichia coli, Staphylococcus aureus, and Streptococcus pyogenes. The highest antibacterial activity...
Targeting Survivin, as an inhibitor of apoptosis and a regulator of cell division, has become a worldwide controversial issue. Piperine as a pungent alkaloid has been identified as the most potent adjuvant at enhancing the efficacy of... more
Targeting Survivin, as an inhibitor of apoptosis and a regulator of cell division, has become a worldwide controversial issue. Piperine as a pungent alkaloid has been identified as the most potent adjuvant at enhancing the efficacy of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-based therapies in triple-negative breast cancer (TNBC) cells in vitro and in vivo, which might be mediated through inhibition of Survivin. In this work, the binding energies, inhibition constants and binding modes of a group of previously synthesized Piperine derivatives at the binding site of Survivin have been studied using molecular docking tools and the best compounds with minimum binding energies are proposed as potential drugs for the inhibition of Survivin. A comprehensive SAR analysis has been done on the results that can be used for designing new Piperine analogs with higher efficacy. Molecular docking computations also show that the studied compounds can bind to BIR domain of Su...
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Free and nanosized starch and lipid encapsulated Na5[PMo10V2O40]·nH2O complexes (abbreviated as PMoV, SEP and LEP, respectively) have been prepared and structurally characterized by Fourier transform infrared (FT-IR) spectroscopy,... more
Free and nanosized starch and lipid encapsulated Na5[PMo10V2O40]·nH2O complexes (abbreviated as PMoV, SEP and LEP, respectively) have been prepared and structurally characterized by Fourier transform infrared (FT-IR) spectroscopy, inductively coupled plasma (ICP) analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The results show that the PMoV retains its parent structure after encapsulation by starch and lipid nanoparticles. The in vitro antitumor activity of PMoV in its free and nano-encapsulated forms was investigated using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay that was carried out on two types of human cancer cells, MCF-7 (breast cancer cells) and HEK-293 (Human Embryonic Kidney). The results represent the enhancement of cell penetration and antitumor activity of PMoV due to its encapsulation in starch or lipid nanoparticles. However, this observed enhancement for the lipid relative to the starch nanocapsule can be attributed to its smaller size. In order to investigate the molecular nature of antitumor activity, the binding properties of PMoV with calf thymus DNA (ctDNA) were also comprehensively evaluated using UV-vis absorption spectroscopy, fluorescence quenching and fluorescence Scatchard plots. The results rule out the intercalating binding mode and propose the groove or outside stacking binding for PMoV. However, a biphasic binding behavior that is due to the change in the binding mode was observed by varying of [PMoV]/[ctDNA] mole ratio. The results of cell culture assay and DNA binding experiments represent that the rate of cell penetration is more important than DNA binding affinity in the antitumor activity for POM.
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... The microcalorimeter was interfaced with an IBM PS 2 model 40486 computer, and the software used was the Thermometric Digitam 3 program. A 1000#1 injection syringe was used. ... 1,5] ZH Zaidi and A. Abbasi, J. Protein Chem., 8 (1989)... more
... The microcalorimeter was interfaced with an IBM PS 2 model 40486 computer, and the software used was the Thermometric Digitam 3 program. A 1000#1 injection syringe was used. ... 1,5] ZH Zaidi and A. Abbasi, J. Protein Chem., 8 (1989) 647. ...
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Bovine serum albumin (BSA) denaturation has been extensively studied by different anionic and cationic surfactant. Dodecyl trimethylammonium bromide (DTAB) is a cationic surfactant, and it is suggested that it binds to the C-terminal... more
Bovine serum albumin (BSA) denaturation has been extensively studied by different anionic and cationic surfactant. Dodecyl trimethylammonium bromide (DTAB) is a cationic surfactant, and it is suggested that it binds to the C-terminal section of BSA. In the present study, the thermodynamical denaturation of BSA by dodecyl trimethylammonium bromide (DTAB) has been studied with various experimental techniques. Equilibrium dialysis, thermal denaturation, gel electrophoresis, titration microcalorimetry at pH 7, I = 0.005, and different temperatures were all performed. The enthalpy obtained from the van't Hoff relation and calorimetry method as well as electrophoresis results were utilized to explain the BSA tranistion state. Major findings included: the binding isotherm shifts at a low free concentrations of DTAB and at a higher temperature suggest endothermicity for enthalpy of interaction; the calorimetry enthalpy (delta Hcal) of interaction was smaller than the van't Hoff enth...
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The binding data for oxygenation of human hemoglobin, Hb, at various temperatures and in the absence and presence of 2,3-diphosphoglycerate, DPG, and inositol hexakis phosphate, IHP, were analyzed for extraction of mean intrinsic Gibbs... more
The binding data for oxygenation of human hemoglobin, Hb, at various temperatures and in the absence and presence of 2,3-diphosphoglycerate, DPG, and inositol hexakis phosphate, IHP, were analyzed for extraction of mean intrinsic Gibbs free energy, DeltaGo, enthalpy, DeltaHo, and entropy, DeltaSo, of binding at various partial oxygen pressures. This method of analysis considers all the protein species present such as dimer and tetramer forms which were not considered by Imai et al. (Imai K et al., 1970, Biochim Biophys Acta 200: 189-196), in their analysis which was based on Adair equation. In this regard, the values of Hill equation parameters were estimated with high precision at all points of the binding curve and used for calculation of DeltaGo, DeltaHo and DeltaSo were also calculated by analysis of DeltaGo values at various temperatures using van't Hoff equation. The results represent the enthalpic nature of the cooperativity in Hb oxygenation and the compensation effect o...
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Binding capacity is the homotropic second derivative of the binding potential with respect to the chemical potential of the ligand. It provides a measure of steepness of the binding isotherm and represents the extent of cooperativity. In... more
Binding capacity is the homotropic second derivative of the binding potential with respect to the chemical potential of the ligand. It provides a measure of steepness of the binding isotherm and represents the extent of cooperativity. In the present study, the shape of the binding capacity curve for various systems was investigated and the relation between binding capacity and the extent of cooperativity examined. In this regard, a novel linear graphical method was introduced for binding data analysis. The stoichiometry of binding and the extent of cooperativity can be determined by this method. This method has been successfully applied to various systems such as binding of oxygen to hemoglobin, warfarin to human serum albumin and dodecyltrimethylammonium bromide to alpha-amylase.
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Biodegradation of lignocellulosic waste by Aspergillus terreus is reported for the first time. This isolate produced 250 CMCase (carboxymethyl cellulase or endoglucanase) U.ml(-1) and biodegraded hay and straw during 3 days and the... more
Biodegradation of lignocellulosic waste by Aspergillus terreus is reported for the first time. This isolate produced 250 CMCase (carboxymethyl cellulase or endoglucanase) U.ml(-1) and biodegraded hay and straw during 3 days and the biomass production on straw was 5g.L(-1) dry weight from 0.25 cm2 inoculated mycellium. This strain secreted endocellulases and exocellulases in the culture medium, but some of the enzymes produced, remained cell membrane bound. Cell bound enzymes were released by various treatments. The highest amount of endoglucanase and exoglucanase was released when the cells were treated with sonication. Aspergillus terreus was added to two tanks containing sugar wastewater and pulp manufacturing waste, as a seed for COD removal. This fungus reduced the COD by 40-80 percent, also, ammonia was reduced from 14.5 mM to 5.6 mM in sugar beet wastewater. The effects of crude enzyme of this fungus for COD removal was studied.
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Two structurally related compounds, phenyl dithiocarbamate sodium salt (I) and p-phenylene-bis (dithiocarbamate) sodium salt (II) were prepared by reaction of the parent aniline and p-phenylenediamine with CS₂ in the presence of sodium... more
Two structurally related compounds, phenyl dithiocarbamate sodium salt (I) and p-phenylene-bis (dithiocarbamate) sodium salt (II) were prepared by reaction of the parent aniline and p-phenylenediamine with CS₂ in the presence of sodium hydroxide. These water soluble compounds were characterized by spectroscopic techniques, IR, ¹H NMR and elemental analysis. The inhibitory effects of both compounds on both activities of mushroom tyrosinase (MT) from Agricus bisporus were studied at two temperatures, 27°C and 37°C. L-3, 4-dihydroxyphenylalanine (L-DOPA), and l-tyrosine were used as natural substrates for the catecholase and cresolase enzyme reactions, respectively. Kinetic analysis confirmed noncompetitive inhibition mode of I and mixed type of II on both activities of MT; I and II inhibit MT with inhibition constants (K(I)) of 300 µM and 4 µM, respectively. Analysis of thermodynamic parameters indicated predominant involvement of hydrophobic interactions in binding of I and electrost...
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ABSTRACT Thermal denaturation of β-lactoglobulin type B in the absence and presence of various concentrations of trehalose, sucrose and sorbitol as sugar osmolytes and polyols were measured by monitoring changes in the absorption... more
ABSTRACT Thermal denaturation of β-lactoglobulin type B in the absence and presence of various concentrations of trehalose, sucrose and sorbitol as sugar osmolytes and polyols were measured by monitoring changes in the absorption coefficients at pH 2.0. These ...
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Gemini surfactants have important advantages, e.g., low micromolar CMCs and slow millisecond monomer ↔ micelle kinetics, for membrane mimetics and for delivering nucleic acids for gene therapy or RNA silencing. However, as a prerequisite,... more
Gemini surfactants have important advantages, e.g., low micromolar CMCs and slow millisecond monomer ↔ micelle kinetics, for membrane mimetics and for delivering nucleic acids for gene therapy or RNA silencing. However, as a prerequisite, it is important to characterize interactions occurring between Gemini surfactants and proteins. Here NMR and CD spectroscopies are employed to investigate the interactions of cationic Gemini surfactants with RNase Sa, a negatively charged ribonuclease. We find that RNase Sa binds Gemini surfactant monomers and micelles at pH values above 4 to form aggregates. Below pH 4, where the protein is positively charged, these aggregates dissolve and interactions are undetectable. Thermal denaturation experiments show that surfactant lowers RNase Sa's conformational stability, suggesting that surfactant binds the protein's denatured state preferentially. Finally, Gemini surfactants were found to bind RNA, leading to the formation of large complexes. Interestingly, Gemini surfactant binding did not prevent RNase Sa from cleaving RNA.
Research Interests: Engineering, RNA, Magnetic Resonance Spectroscopy, Protein Stability, Micelles, and 11 moreCircular Dichroism, Physical sciences, Temperature, CHEMICAL SCIENCES, Surface Active Agents, Quaternary Ammonium Compounds, Cations, Hydrogen-Ion Concentration, Protein Denaturation, Static Electricity, and Ribonucleases
ABSTRACT The interaction of gallium maltolate (Ga(ma)3) with human serum transferrin has been investigated by means of UV–Vis spectroscopy and isothermal titration calorimetry. First, the values of the first and second associative... more
ABSTRACT The interaction of gallium maltolate (Ga(ma)3) with human serum transferrin has been investigated by means of UV–Vis spectroscopy and isothermal titration calorimetry. First, the values of the first and second associative stepwise binding constants of Ga(ma)3 to apotransferrin were estimated by use of a data analyzing method. The synergistic role of the carbonate anion in the formation of gallium-transferrin bonds was also investigated. Experimental results indicated that the extent of binding is maximum at physiological pH. Citrate ion and transferrin have a competitive behavior toward gallium binding. By use of the calorimetric results, the values of 23.44 and 8.99 kJ mol−1 were determined for the associative stepwise enthalpy changes. This represents the endothermic entropy-driven nature of the process.
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Research Interests: Fluorescence and European
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The thermodynamic of the binding of nickel (II) tetrasulfonated phthalocyanine anion [Ni(tspc)4–], to human serum albumin (HSA) was investigated in 5 mM aqueous phosphate buffer of pH 7.40 at 25°C using optical absorption spectroscopy.... more
The thermodynamic of the binding of nickel (II) tetrasulfonated phthalocyanine anion [Ni(tspc)4–], to human serum albumin (HSA) was investigated in 5 mM aqueous phosphate buffer of pH 7.40 at 25°C using optical absorption spectroscopy. The results show that [Ni(tspc)4–] does not have any affinity for aggregation due to increasing of salt concentration and exists as monomers even in homogeneous aqueous solutions of high ionic strengths (more than 2 M NaCl). The binding constant (K) was obtained by analysis of optical absorption spectra of mentioned complex at various HSA concentrations using SQUAD software. The value ofKwas estimated to be 4.89×105±0.03 (M–1) at 25°C. The thermodynamic parameters were calculated by van’t Hoff equation. The enthalpy and entropy changes were 28.08 kJ/mol and 203.09 J/(mol?·?K) at 25°C, respectively. The results indicate that the binding is mainly entropy driven and the enthalpy is unfavorable for it, the hydrophobic forces thus playing a major role in ...
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In this work, docking tools were utilized in order to study the binding properties of more than five hundred of proline-based 2,5-diketopiperazine in the binding site of αβ-tubulin. Results revealed that 20 compounds among them showed... more
In this work, docking tools were utilized in order to study the binding properties of more than five hundred of proline-based 2,5-diketopiperazine in the binding site of αβ-tubulin. Results revealed that 20 compounds among them showed lower binding energies in comparison with Tryprostatin-A, a well known tubulin inhibitor and therefore could be potential inhibitors of tubulin. However, the precise evaluation of binding poses represents the similar binding modes for all of these compounds and Tryprostatin-A. Finally, the best docked complex was subjected to a 25 ns molecular dynamics simulation to further validate the proposed binding mode of this compound.
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Research Interests:
Isothermal titration calorimetry (ITC) was utilized at conditions close to physiological (50 mM HEPES buffer, pH 7.4 and 160 mM NaCl) and at various temperatures of 25, 30, 35 and 40 °C to evaluate the thermodynamic parameters, enthalpy... more
Isothermal titration calorimetry (ITC) was utilized at conditions close to physiological (50 mM HEPES buffer, pH 7.4 and 160 mM NaCl) and at various temperatures of 25, 30, 35 and 40 °C to evaluate the thermodynamic parameters, enthalpy and heat capacity changes, and subsequently the unfolding process of apo-human serum tarnsferrin (apo-hTf) in the presence of cetylpyridinium chloride (CPC) as a cationic surfactant. The precise thermograms and heat capacity curves obtained and interpreted in terms of molecular events such as specific and non-specific binding and the unfolding process. The analysis of obtained enthalpograms and heat capacity changes profile showed a distinct extreme region close to [CPC]/[apo-hTf] mole ratio of 20 indicated that predominant cooperative unfolding occurs at this mole ratio via a two states mechanism.
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Magnetite Fe3O4nanoparticles (NPs) were prepared by chemical coprecipitation method. Silica-coated magnetite NPs were prepared by sol-gel reaction, subsequently coated with 3-aminopropyltriethoxysilane (APTES) via silanization reaction,... more
Magnetite Fe3O4nanoparticles (NPs) were prepared by chemical coprecipitation method. Silica-coated magnetite NPs were prepared by sol-gel reaction, subsequently coated with 3-aminopropyltriethoxysilane (APTES) via silanization reaction, and then were activated with 2,4,6-trichloro-1,3,5-triazine (TCT) and covalently immobilized with bovine serum albumin (BSA). The size and structure of the particles were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and dynamic light scattering (DLS) techniques. The immobilization was confirmed by Fourier transform infrared spectroscopy (FT-IR). XRD analysis showed that the binding process has not done any phase change to Fe3O4. The immobilization time for this process was 4 h and the amount of immobilized BSA for the initial value of 1.05 mg BSA was about 120 mg/gr nanoparticles. Also, the influences of three different buffer solutions and ionic strength on covalent immobilization were evaluated.
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Research Interests:
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... A four channel microcalorimetric system, Thermal Activity Monitor 2277 from Sweden Thermometric, interfaced with an IBM Pentium III and DIGITAM-3 software and a 1000 μl injection syringe for enthalpy measurements at 27.000±0.005 °C... more
... A four channel microcalorimetric system, Thermal Activity Monitor 2277 from Sweden Thermometric, interfaced with an IBM Pentium III and DIGITAM-3 software and a 1000 μl injection syringe for enthalpy measurements at 27.000±0.005 °C were used. ... 5. ZH Zaidi and A. Abbasi. ...
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Research Interests: Genetics, Structure, Fluorescence, Protein, Fluorescence Resonance Energy Transfer, and 15 moreInteractions, Protein Chemistry, Circular Dichroism, Curcumin, Animals, Ligand Binding, Cattle, Secondary Structure, Energy Transfer, Protein Binding, Binding Site, Biochemistry and cell biology, Fluorescence quenching, binding sites, and Optical Activity
Research Interests: Fluorescence, Humans, Interactions, Circular Dichroism, Curcumin, and 15 moreAnimals, Ligand Binding, Cattle, Circular Dichroism Spectroscopy, Human Serum, Energy Transfer, Bovine Serum Albumin, Active Ingredient, Binding Site, Conformational Change, Biochemistry and cell biology, Fluorescence quenching, binding sites, Optical Activity, and Human serum albumin
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The interaction of jack bean urease with dodecyl trimethylammonium bromide (DTAB), tetradecyl trimethylammonium bromide (TTAB), and hexadecyl trimethylammonium bromide (HTAB) was studied by microcalorimetry atT= 300 K and equilibrium... more
The interaction of jack bean urease with dodecyl trimethylammonium bromide (DTAB), tetradecyl trimethylammonium bromide (TTAB), and hexadecyl trimethylammonium bromide (HTAB) was studied by microcalorimetry atT= 300 K and equilibrium dialysis at temperatures of 300 K and 310 K in alkaline solution at PH = 10.0. The enthalpy of binding was calculated from binding data with were obtained from equilibrium dialysis
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The DNA binding properties of a bulky and hydrophobic Schiff base complex of manganese(III) [N,N'-bis(5-(triphenyl phosphonium... more
The DNA binding properties of a bulky and hydrophobic Schiff base complex of manganese(III) [N,N'-bis(5-(triphenyl phosphonium methyl)salicylidene)-1,2-ethylene diamine chloride Mn(III) acetate] was examined by spectroscopic techniques. UV-vis titration data indicate both hypo and hyperchromic effect with addition of DNA to complex. A competitive binding study showed that the enhanced emission intensity of ethidium bromide (EB) in the presence of DNA was quenched by adding Mn Salen complex. This finding indicates that Mn Salen complex displaces EB from its binding site in DNA. Helix melting studies indicate improvement in the helix stability, and an increase in the melting temperature. The analysis of CD spectra represents the structural changes in DNA due to the binding of Mn Salen complex. The binding constant has been calculated using absorbance and fluorescence data. The results also represent that the binding process proceeds by strong electrostatic and hydrophobic interactions.
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The interaction of diacetylcurcumin (DAC), as a novel synthetic derivative of curcumin, with bovine β-casein (an abundant milk protein that is highly amphiphilic and self assembles into stable micellar nanoparticles in aqueous solution)... more
The interaction of diacetylcurcumin (DAC), as a novel synthetic derivative of curcumin, with bovine β-casein (an abundant milk protein that is highly amphiphilic and self assembles into stable micellar nanoparticles in aqueous solution) was investigated using fluorescence quenching experiments, Forster energy transfer measurements and molecular docking calculations. The fluorescence quenching measurements revealed the presence of a single binding site on β-casein for DAC with the binding constant value equals to (4.40±0.03)×10(4)M(-1). Forster energy transfer measurements suggested that the distance between bound DAC and Trp143 residue is higher than the respective critical distance, hence, the static quenching is more likely responsible for fluorescence quenching other than the mechanism of non-radiative energy transfer. Our results from molecular docking calculations indicated that binding of DAC to β-casein predominantly occurred through hydrophobic contacts in the hydrophobic core of protein. Additionally, in vitro investigation of the cytotoxicity of free DAC and DAC-β-casein complex in human breast cancer cell line MCF7 revealed the higher cytotoxic effect of DAC-β-casein complex.
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The molecular mechanism of a Schiff base complex ((E)-((E)-2-(3-((E)-((E)-3(mercapto (methylthio) methylene)cyclopentylidene) amino) propylimino) cyclopentylidene) (methylthio) methanethiol) binding to Human Serum Albumin (HSA) was... more
The molecular mechanism of a Schiff base complex ((E)-((E)-2-(3-((E)-((E)-3(mercapto (methylthio) methylene)cyclopentylidene) amino) propylimino) cyclopentylidene) (methylthio) methanethiol) binding to Human Serum Albumin (HSA) was investigated by fluorescence quenching, absorption spectroscopy, molecular docking and molecular dynamics (MD) simulation procedures. The fluorescence emission of HSA was quenched by this Schiff base complex that has been analyzed for estimation of binding parameters. The titration of Schiff base solution by various amount of HSA was also followed by UV-Vis absorption spectroscopy and the corresponding data were analyzed by suitable models. The results revealed that this Schiff base has an ability to bind strongly to HSA and formed 1:1 complex. Energy transfer mechanism of quenching was discussed and the value of 5.45 ± 0.06 nm was calculated as the mean distance between the bound complex and the Trp residue. This is implying the high possibility of energy transfer from HSA to this Schiff base complex. Molecular docking results indicated that the main active binding site for this Schiff base complex is site III in subdomain IB. Moreover, MD simulation results suggested that this Schiff base complex can interact with HSA, without affecting the secondary structure of HSA but probably with a slight modification of its tertiary structure. MD simulations, molecular docking and experimental data reciprocally supported each other.
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In the present study, at first, N,N′-bis(3,4-dihydroxyhenzylidene)-1,2-diaminobenzene (BDBDAB), has been synthesized by combination of 1,2-diaminobenzene and 3,4-dihydroxybenzaldehyde in a solvent system. These ligand containing... more
In the present study, at first, N,N′-bis(3,4-dihydroxyhenzylidene)-1,2-diaminobenzene (BDBDAB), has been synthesized by combination of 1,2-diaminobenzene and 3,4-dihydroxybenzaldehyde in a solvent system. These ligand containing ortho-quinone functional groups were characterized using UV-VIS and IR spectroscopies. Subsequently, the interaction between native calf thymus deoxyribonucleic acid (ct-DNA) and BDBDAB was investigated in 10 mM Tris-HCl buffer solution, pH 7.2, using UV-visible absorption and
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Heat stress on structure and ligand binding of beta-LG has been studied by fluorescence, circular dichroism and gel electrophoresis at pH 6.5. Native PAGE gel electrophoresis shows that denaturation of beta-LG is reversible up to 75... more
Heat stress on structure and ligand binding of beta-LG has been studied by fluorescence, circular dichroism and gel electrophoresis at pH 6.5. Native PAGE gel electrophoresis shows that denaturation of beta-LG is reversible up to 75 degrees C then it becomes irreversible due to aggregation of beta-LG. Formation of aggregated beta-LG is completed at 95 degrees C. Circular dichroism results indicate that formation of aggregated beta-LG is accompanied by the scrambling of disulfide bonds (creation of new intramolecular and intermolecular disulfide bridges and rearrangement of old intramolecular disulfide bridges). Addition of ethanolic retinol causes a change in polarity of the solution and favors transformation of the beta<-->alpha structure. In the presence of retinol, the alpha-helix content of the secondary structure of heat-treated beta-LG is increased and the major portion of its secondary structure is helical. Fluorescence results show that heat-treated beta-LG at 95 degrees C can still bind retinol. The refolding of the tertiary structure of beta-LG heat-denatured at 95 degrees C may recreate a retinol binding site. Surprisingly, the affinity of the new site for retinol is higher than that of native beta-LG; however, the apparent molar ratio is lower than one. The binding properties of beta-LG for terpenoids have been measured after its heat treatment at 20, 75 and 95 degrees C. The intensity of tryptophan emission at 330 nm was changed only in the case of the interaction with beta-ionone. Other ligands probably cannot bind to beta-LG or they bind in a binding site far from the tryptophan residues, hence not affecting its fluorescence.
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... 4, August 2007, 435441 Thermodynamic analysis for cationic surfactants binding to bovine serum albumin ABDOL-KHALEGH BORDBAR* and ELHAM HOJJATI Laboratory of Biophysical Chemistry, Department of Chemistry, Isfahan University, Isfahan... more
... 4, August 2007, 435441 Thermodynamic analysis for cationic surfactants binding to bovine serum albumin ABDOL-KHALEGH BORDBAR* and ELHAM HOJJATI Laboratory of Biophysical Chemistry, Department of Chemistry, Isfahan University, Isfahan 81746-73441, Iran ...
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Interactions of three water soluble porphyrins, tetra (p-trimethyl) ammonium phenyl porphyrin iodide (TAPP) as a cationic porphyrin, tetra sodium meso-tetrakis (p-sulphonato phenyl) porphyrin (TSPP) as an anionic porphyrin, and manganese... more
Interactions of three water soluble porphyrins, tetra (p-trimethyl) ammonium phenyl porphyrin iodide (TAPP) as a cationic porphyrin, tetra sodium meso-tetrakis (p-sulphonato phenyl) porphyrin (TSPP) as an anionic porphyrin, and manganese tetrakis (p-sulphonato phenyl) ...
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... 127133 STUDY OF INTERACTION OF POTASSIUM DODECATANGESTATO COBALTATE( III) WITH BOVINE SERUM ALBUMIN USING FLUORESCENCE SPECTROSCOPYABDOL-KHALEGH BORDBAR*, NASRIN SOHRABI and SHAHRAM TANGESTANINEJAD ...
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ABSTRACT The micellar properties of β-casein in solution with a homologous series of cationic surfactants have been investigated using turbidity, fluorescence spectroscopy, and quenching fluorescence measurements. Turbidity measurements... more
ABSTRACT The micellar properties of β-casein in solution with a homologous series of cationic surfactants have been investigated using turbidity, fluorescence spectroscopy, and quenching fluorescence measurements. Turbidity measurements indicated that monomeric cationic surfactants initially bind cooperatively with a site on the β-casein micelle in negatively charged amino acids. This leads to the formation of low-soluble β-casein micelle-monomeric surfactants complexes. Further addition of surfactant leads to the formation of more highly soluble complexes of β-casein micelle-cationic surfactant. The fluorescence experiments were also used to study the formation of β-casein–cationic surfactant complexes and to determine critical micelle concentration of surfactants and β-casein. The mean aggregation number of β-casein and cationic surfactant micelles at various experimental conditions and the dependence of aggregation phenomenon on the chain length of cationic surfactants were investigated. The mean aggregation number for β-casein micelle has been determined to be 45.70 using quenching fluorescence. Graphical Abstract .
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Research Interests:
ABSTRACT Isothermal titration calorimetry (ITC) was utilized at conditions close to physiological (50 mM HEPES buffer, pH 7.4 and 160 mM NaCl) and at various temperatures (20, 25, 30, 35 and 40◦C) to evaluate the enthalpy and heat... more
ABSTRACT Isothermal titration calorimetry (ITC) was utilized at conditions close to physiological (50 mM HEPES buffer, pH 7.4 and 160 mM NaCl) and at various temperatures (20, 25, 30, 35 and 40◦C) to evaluate the enthalpy and heat capacity changes for the interactions of sodium n-dodecyl sulfate (SDS) as an anionic surfactant with apo-human tarnsferrin (apo-hTf). The obtained results are very informative due to importance of heat capacity change as a major thermodynamic quantity that is one of the richest potential sources of information in physical terms. The obtained precise thermograms and heat capacity curves were interpreted in terms of molecular events such as specific and non-specific binding and the unfolding process. A three step mechanism for the interaction of SDS with apo-hTf has been figured out on basis of ITC studies: , where N, I and D correspond to native, partially unfolded and denatured states, respectively.
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Abstract The micellization characteristics of sodium n-dodecyl sulfate (SDS) have been investigated by micro-calorimetric technique at conditions close to the physio-logical ones. The thermodynamics of micellization were studied at 20,... more
Abstract The micellization characteristics of sodium n-dodecyl sulfate (SDS) have been investigated by micro-calorimetric technique at conditions close to the physio-logical ones. The thermodynamics of micellization were studied at 20, 25, 30, 35 and 40 °C in 50 mM HEPES buffer, pH 7.4 ...
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ABSTRACT Aggregation behavior of water soluble porphyrins, 5-(1-(4-carboxybutyl) pyridinum-4-yl) 10,15,20-tris (1-methylpyridinium-4-yl) porphyrin (5-CBPyP) in the presence of various concentrations of calf thymus DNA (ct-DNA) and sodium... more
ABSTRACT Aggregation behavior of water soluble porphyrins, 5-(1-(4-carboxybutyl) pyridinum-4-yl) 10,15,20-tris (1-methylpyridinium-4-yl) porphyrin (5-CBPyP) in the presence of various concentrations of calf thymus DNA (ct-DNA) and sodium chloride were studied in comparison with meso-tetrakis (4-N-methyl pyridinum) porphyrin (TMPyP), by optical absorption, fluorescence and resonance light scattering (RLS) spectroscopies. Both porphyrins obey Beer’s law in extended range of concentration. Optical absorption and RLS measurements demonstrated nonaggregation for both porphyrins under increasing concentration of ct-DNA and NaCl. However, in comparison, 5-CBPyP had less tendency for aggregation that may be taken as an advantage for its probable application in photodynamic therapy of cancer. The trend of changes in absorption spectra of both porphyrins in the presence of ct-DNA indicates the homogeneous intercalation binding mode. The values of (2.81 ± 0.28) × 106 M−1 and (0.95 ± 0.09) × 106 M−1 were obtained for apparent binding constant of TMPyP and 5-CBPyP from analysis of optical absorption data, respectively. This indicates the less affinity of 5-CBPyP to ct-DNA in comparison with TMPyP. The binding of both porphyrins to ct-DNA quenches fluorescence emission of Ethidium bromide (EB) that is bound to ct-DNA. The quenching process obeys linear Stern-Volmer relationship indicating the displacement of EB from its binding sites by these porphyrins. The results of this technique also represent the intercalation mode of binding for both porphyrins and higher binding affinity of TMPyP compared with 5-CBPyP.
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Research Interests:
Pentanediyl-1,5-bis (hydroxyethylmethylhexadecylammonium bromide) was synthesized and characterized as a type of novel gemini cationic surfactant. Its solution properties were determined at various temperatures by conductivity... more
Pentanediyl-1,5-bis (hydroxyethylmethylhexadecylammonium bromide) was synthesized and characterized as a type of novel gemini cationic surfactant. Its solution properties were determined at various temperatures by conductivity measurements and the fluorescence quenching technique. The CMC increased in the range of 1.85 to 2.77 μmol⋅L−1 as the temperature increased. The aggregation number was determined at various concentrations of NaBr solutions by the fluorescence quenching
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The association behavior of tetrakis( N , N ′, N ″, N ‴-tetramethyl tetra-2,3-pyridino)porphyrazine copper(II) ([ Cu(II) 2,3- tmtppa ]4+) was investigated in aqueous solutions at 25 °C and various ionic strengths using optical absorption... more
The association behavior of tetrakis( N , N ′, N ″, N ‴-tetramethyl tetra-2,3-pyridino)porphyrazine copper(II) ([ Cu(II) 2,3- tmtppa ]4+) was investigated in aqueous solutions at 25 °C and various ionic strengths using optical absorption and resonance light scattering (RLS) spectroscopies. The results show that ([ Cu(II) 2,3- tmtppa ]4+) does not have any affinity for aggregation due to increasing of salt concentration and exists as monomers even in homogeneous aqueous solutions of high ionic strengths (more than 1 M NaCl ). Interaction of ([ Cu(II) 2,3- tmtppa ]4+) with calf thymus DNA has also been studied in 1 mM aqueous phosphate buffer of pH 7.0, by optical absorption and RLS spectroscopies, and thermal denaturation experiments. The appearance of hypochromicity of less than 10% and bathochromicity shift of Δλ ≤ 2 nm in UV-vis spectra of ([ Cu(II) 2,3- tmtppa ]4+), increasing of thermal melting point of DNA, and no change in RLS spectra of porphyrazine due to interaction with DN...
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The equilibrium binding of the tetra-cationic complexes ( N , N ′, N ″, N ‴-tetra-methyltetra-2,3-pyridinoporphyrazinato)copper(II), ([ Cu (2,3- TMTPPA )]4+), ( N , N ′, N ″, N ‴-tetra-methyltetra-3,4-pyridinoporphyrazinato)copper(II), ([... more
The equilibrium binding of the tetra-cationic complexes ( N , N ′, N ″, N ‴-tetra-methyltetra-2,3-pyridinoporphyrazinato)copper(II), ([ Cu (2,3- TMTPPA )]4+), ( N , N ′, N ″, N ‴-tetra-methyltetra-3,4-pyridinoporphyrazinato)copper(II), ([ Cu (3,4- TMTPPA )]4+), (( N , N ′, N ″, N ‴-tetra-methyltetra-3,4-pyridinoporphyrazinato)cobalt(II), ([ Co (3,4- TMTPPA )]4+) and (( N , N ′, N ″, N ‴-tetra-methyltetra-3,4-pyridinoporphyrazinato)zinc(II), ([ Zn (3,4- TMTPPA )]4+) with bovine serum albumin (BSA) has been studied in phosphate buffer pH = 7.0 and at various temperatures using multi-spectroscopy techniques. The results of resonance light scattering (RLS) studies represent no aggregate formation of porphyrazine in the surface of BSA and low tendency of these porphyrazine for aggregate formation. The binding constants and binding stoichiometries were determined by analyzing of optical absorption spectra of porphyrazine complexes at various concentration of BSA using SQUAD software. The ...
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Binding properties of two water-soluble porphyrins, manganese(III) 5-(1-(4-carboxybutyl)pyridinium-4-yl) 10,15,20-tris(1-methylpyridinium-4-yl)porphyrin ( Mn(III)5-CBPyP ) and manganese(III)... more
Binding properties of two water-soluble porphyrins, manganese(III) 5-(1-(4-carboxybutyl)pyridinium-4-yl) 10,15,20-tris(1-methylpyridinium-4-yl)porphyrin ( Mn(III)5-CBPyP ) and manganese(III) 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin ( Mn(III)TMPyP ), in the presence of various concentration of calf thymus DNA (ct-DNA), has been studied in 7.5 mM phosphate buffer, pH = 7.2 and at various temperatures by UV-vis absorption, resonance light scattering (RLS) and fluorescence spectroscopy and viscosity measurement. Optical absorption and RLS measurements have demonstrated three different species of both porphyrins form in DNA solution. The thermodynamic parameters were calculated by van't Hoff equation at various temperatures. The values of -4.89 kJ.mol-1 and +65.98 J.mol-1.K-1 for Mn(III)5-CBPyP and -14.92 kJ.mol-1 and +15.46 J mol-1.K-1 for TMPyP were estimated for enthalpy and entropy changes of interaction, respectively. The data indicate that the process is exothermic...
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The association behavior of tetrakis( N , N ', N ″, N ‴-tetramethyltetra-3,4-pridino)porphyrazine cobalt(II) ([ Co (II)3,4- TMTPPA ]4+) was investigated in aqueous solution at 25°C and various ionic strengths using optical absorption... more
The association behavior of tetrakis( N , N ', N ″, N ‴-tetramethyltetra-3,4-pridino)porphyrazine cobalt(II) ([ Co (II)3,4- TMTPPA ]4+) was investigated in aqueous solution at 25°C and various ionic strengths using optical absorption and resonance light scattering spectroscopies. The results show that [ Co (II)3,4- TMTPPA ]4+ does not have any affinity for aggregation due to increasing salt concentration and exists as the monomer form even in homogeneous aqueous solutions at high ionic strengths (more than 1 M concentration of NaCl ). The interaction of [ Co (II)3,4- TMTPPA ]4+ with calf thymus DNA in aqueous solution has also been studied in 5 mM phosphate buffer pH 7.2, by optical absorption and resonance light scattering spectroscopies, and thermal denaturation experiments. The appearance of hypochromicity of less than 10% and a bathochromic shift of Δλ ≤ 8 nm in the UV-vis spectra of [ Co (II)3,4- TMTPPA ]4+, an increase in the thermal melting point of DNA, and no enhancemen...
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The association behavior of 5,10,15,20-tetrakis(4-N-benzyl-pyridyl)porphyrin ( TBzPyP ) was investigated in aqueous solution at 27 °C and various ionic strengths by optical absorption, fluorescence and resonance light scattering (RLS)... more
The association behavior of 5,10,15,20-tetrakis(4-N-benzyl-pyridyl)porphyrin ( TBzPyP ) was investigated in aqueous solution at 27 °C and various ionic strengths by optical absorption, fluorescence and resonance light scattering (RLS) spectroscopies. The results show that TBzPyP exists as monomer at low ionic strength and as ill-defined aggregates at high ionic strength and does not show concentration dependent aggregation over an extended concentration range between 5 × 10−7 to 1 × 10−4 M in water. The interaction of the TBzPyP with human serum albumin (HSA) in 5 mM phosphate buffer, pH = 7.00, and at 27 °C, has been also studied by optical absorption, fluorescence and RLS spectroscopies. The formation of two types of complexes (HSA: TBzPyP and (HSA)2: TBzPyP ) has been demonstrated by analysis of optical absorption spectral patterns of TBzPyP at various concentrations of HSA. Based on absorption data, a binding model has been proposed and used to analyze the binding process. The c...
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The interaction of quercetin with β-casein nanoparticle micelle was studied at various temperatures in order to do a complete thermodynamic and molecular analysis on the binding process. The results of fluorescence studies showed the... more
The interaction of quercetin with β-casein nanoparticle micelle was studied at various temperatures in order to do a complete thermodynamic and molecular analysis on the binding process. The results of fluorescence studies showed the possibility of fluorescence energy transfer between excited tryptophan and quercetin. The determined values of critical transfers distance and the mean distance of ligand from Trp-143 residues in β-casein micelle represents a non-radiative energy transfer mechanism for quenching and the existence of a significant interaction between this flavonoid and β-casein nanoparticle. The equilibrium binding of quercetin with β-casein micelle at different temperatures was studied by using UV-Vis absorption spectroscopy. The chemometric analysis (principal component analysis (PCA) and multivariate curve resolution-alternating least squares (MCR-ALS) methods) on spectrophotometric data revealed the existence of two components in solution (quercetin and β-casein-quercetin complex) and resolved their pure concentration and spectral profiles. This information let us to calculate the equilibrium binding constant at various temperatures and the relevant thermodynamic parameters of interaction (enthalpy, entropy and Gibbs free energy) with low uncertainty. The negative values of entropy and enthalpy changes represent the predominate role of hydrogen binding and van der Waals interactions in the binding process. Docking calculations showed the probable binding site of quercetin is located in the hydrophobic core of β-casein where the quercetin molecule is lined by hydrophobic residues and make five hydrogen bonds and several van der Waals contacts with them. Moreover, molecular dynamic (MD) simulation results suggested that this flavonoid can interact with β-casein, without affecting the secondary structure of β-casein. Simulations, molecular docking and experimental data reciprocally supported each other.
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The ctDNA-binding properties and in vitro antitumor activity of three water soluble Keggin type polyoxometalates (POMs): K6H[CoW11O39CpZr]·nH2O, K6H[CoW11O39CpTi·nH2O and K7H2[CoW11O39CpFe]·nH2O (abbreviated as CoWCpZr, CoWCpTi and... more
The ctDNA-binding properties and in vitro antitumor activity of three water soluble Keggin type polyoxometalates (POMs): K6H[CoW11O39CpZr]·nH2O, K6H[CoW11O39CpTi·nH2O and K7H2[CoW11O39CpFe]·nH2O (abbreviated as CoWCpZr, CoWCpTi and CoWCpFe, respectively) were investigated using UV-Vis absorption spectroscopy, fluorescence spectrophotometry, cyclic voltammetry and MTT assay. The results of UV-Vis, fluorescence and cyclic voltammetry rule out intercalating binding mode and propose the groove or outside stacking binding of these POMs with ctDNA. The values of 1.30×10(4) M(-1), 1.15×10(4) M(-1) and 3.10×10(3) M(-1) were obtained for binding constant of CoWCpZr, CoWCpTi and CoWCpFe to ctDNA, respectively. The redox potential of POMs shift to more negative values in the presence of ctDNA which can be related to domination of electrostatic interaction in this system. The antitumor activity tests of these polyoxometalates (POMs) were carried out on two types of human cancer cells, MCF-7 and HEK-293 by MTT method. The results show the higher antitumor activity of CoWCpFe respect to two other that is related to its highest penetrating effectiveness for MCF-7 cells. Therefore, the antitumor activity of these POMs depends not only on their affinity to ctDNA but also strongly on their penetration ability to the cell membrane.
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Research Interests:
The thermodynamic of the binding of N,N′,N″,N -tetramethyltetra-2,3-pyridinoporphyrazinatocopper (II) ([Cu(2,3-tmtppa)] 4+ ), N,N′,N″,N -tetramethyltetra-3,4-pyridinoporphyrazinatocopper(II ) ([Cu(3,4-tmtppa)] 4+ ), N,N′,N″,N... more
The thermodynamic of the binding of N,N′,N″,N -tetramethyltetra-2,3-pyridinoporphyrazinatocopper (II) ([Cu(2,3-tmtppa)] 4+ ), N,N′,N″,N -tetramethyltetra-3,4-pyridinoporphyrazinatocopper(II ) ([Cu(3,4-tmtppa)] 4+ ), N,N′,N″,N -tetramethyltetra-3,4-pyridinoporphyrazinatocobalt(II ...
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ABSTRACT Polyoxometalates (POMs) have shown a great potential of antitumor and antiviral activities; take into account, in this work we investigated the stability of a series of heteropolyoxotungstate-amino acids,... more
ABSTRACT Polyoxometalates (POMs) have shown a great potential of antitumor and antiviral activities; take into account, in this work we investigated the stability of a series of heteropolyoxotungstate-amino acids, heteropolyoxomolybdate-amino acids and the corresponding 12-heteropoly acids at different experimental conditions such as pH, buffer concentration, and the type of counter ion using UV–vis spectroscopy. Furthermore, the effect of tyrosine and ornithine were investigated as a counter ion, on the stability of POMs. The results indicated that degradation of these POMs in aqueous solutions follows pseudo-first order reaction kinetics according to the order of H4SiW12O40 > H3PW12O40 > H4SiMo12O40 > H3PMo12O40 for stability with respect to increasing of pH. The stability of POM increases in the presence of these amino acids.
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Research Interests:
ABSTRACT This study was designed to examine the interaction of two Schiff base complexes with human serum albumin (HSA), by different kinds of spectroscopic and molecular modeling techniques. Fluorescence quenching and absorption spectra... more
ABSTRACT This study was designed to examine the interaction of two Schiff base complexes with human serum albumin (HSA), by different kinds of spectroscopic and molecular modeling techniques. Fluorescence quenching and absorption spectra were investigated in order to estimate the binding parameters. The analysis of absorption data at different temperatures were done in order to estimate the thermodynamics parameters of interactions between Schiff base complexes and HSA. The experimental data suggested that both complexes demonstrated a significant binding affinity to HSA and the process is enthalpy driven. Molecular docking study indicated that both Schiff base complexes bind to polar and apolar residues located in the subdomain IB of HSA. Molecular dynamics (MD) simulations were also performed with the GROMACS program package to study the characters of HSA in binding states. Molecular dynamics results suggested that both Schiff base complexes can interact with HSA, without affecting the secondary structure of HSA but probably with a slight modification of its tertiary structure. All the molecular docking and molecular dynamics results kept in good consistence with experimental data.
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Research Interests:
Research Interests: Inorganic Chemistry, Kinetics, Inorganic, Type 2 Diabetes, Humans, and 14 moreInsulin, Differential scanning calorimetry, Transferrin, Thermal Stability, Oral Hypoglycemic Agents, Human Serum, Isothermal Titration Calorimetry, Calorimetry, Inorganic Biochemistry, Type 2 Diabetes Mellitus, Hydrogen-Ion Concentration, Apoproteins, Vanadates, and Drug synergism
ABSTRACT We described a green, cost effective and rapid method for synthesizing anisotropic AgNPs using a novel bacterium called Escherichia fergusoni. Furthermore, synthesized AgNPs were characterized by various analytical techniques.... more
ABSTRACT We described a green, cost effective and rapid method for synthesizing anisotropic AgNPs using a novel bacterium called Escherichia fergusoni. Furthermore, synthesized AgNPs were characterized by various analytical techniques. The present study demonstrates the efficiency of biologically synthesized AgNPs as a cytotoxic agent against MCF-7 cells and also this study investigates possible molecular mechanisms underlying the cytotoxic effects of AgNPs. AgNPs showed dose dependent cytotoxicity against MCF-7 cells through activation of the lactate dehydrogenase (LDH), reactive oxygen species (ROS) generation and eventually leading to induction of apoptosis which was further confirmed through resulting nuclear fragmentation.
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In this work, binding of two water soluble Schiff base complexes: Bis sodium (5-sulfosalicylaldehyde) o-phenylendiiminato) Manganese (III) acetate (Salophen complex) and Bis sodium (5-sulfosalicylaldehyde) 1, 2 ethylendiiminato) Manganese... more
In this work, binding of two water soluble Schiff base complexes: Bis sodium (5-sulfosalicylaldehyde) o-phenylendiiminato) Manganese (III) acetate (Salophen complex) and Bis sodium (5-sulfosalicylaldehyde) 1, 2 ethylendiiminato) Manganese (III) acetate (Salen complex) with calf thymus (ct) DNA were investigated by using different spectroscopic and electrometric techniques including UV-vis, Circular dichroism (CD) and fluorescence spectroscopy, viscommetry and cyclic voltammetry (CV). Both complexes have shown a hyperchromic and a small bathochromic shift in the visible region spectra. A competitive binding study showed that the enhanced emission intensity of ethidium bromide (EB) in the presence of DNA was quenched by the addition of the two Schiff base complexes indicating that they displace EB from its binding site in DNA. Moreover structural changes in the CD spectra and an increase in the CV spectra with addition of DNA were observed. The results show that both complexes bind to DNA. The binding constants have been calculated using fluorescence data for two complexes also K(b) was calculated with fluorescence Scatchard plot for Salophen. Ultimately, the experimental results show that the dominant interactions are electrostatic while binding mode is surface binding then followed by hydrophobic interactions in grooves in high concentration of complexes.
Research Interests: Analytical Chemistry, Fluorescence Spectroscopy, Electrochemistry, Fluorescence, Cyclic Voltammetry, and 15 moreManganese, DNA, Circular Dichroism, Animals, Schiff bases, Cattle, Schiff Base, Organometallic Compounds, Protein Denaturation, Sodium Chloride, Binding Site, Molecular Structure, Ethidium bromide, binding sites, and Scatchard plot
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Research Interests:
In the first part of this work, binding energies, inhibition constants and binding modes for a group of previously synthesized Tryprostatin-A (TPS-A) derivatives at the binding site of αβ-tubulin have been comprehensively investigated by... more
In the first part of this work, binding energies, inhibition constants and binding modes for a group of previously synthesized Tryprostatin-A (TPS-A) derivatives at the binding site of αβ-tubulin have been comprehensively investigated by molecular docking study. The results represent relatively suitable binding energies for these inhibitors in the αβ-tubulin binding site. In the second part, docking tools were utilized in order to design a group of novel analogues of TPS-A. The results of molecular docking reveal that these newly designed molecules have relatively lower binding energies in the pocket of αβ-tubulin. Compound 26 resulted as the best docked molecule with the highest binding affinity (binding energy of -10.74 kcal/mol and calculated inhibition constant of 13.44 nM). In the last part of this study, three representative complexes were subjected to a 25 ns molecular dynamics simulation to further validate the proposed binding modes and interactions. Analysis of the simulation trajectories showed that the root mean square deviation (RMSD) profile of compound 26 was fairly stable during the whole simulation time, indicating that the orientation generated from the docking study is fairly well preserved during the entire length of the simulation. Moreover, the RMSD profiles of compounds 4 and 31 were probably stable in relation to αβ-tubulin after 7 and 14 ns, and these molecular systems were well behaved thereafter. The results of the current study shed some light on the binding mode of TPS-A analogues for further experimental studies.
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Bovine beta-lactoglobulin (beta-LG) in vivo (in milks) has been found in complexes with lipids such as butyric and oleic acids. To elucidate the still unknown structure-function relationship in this protein, the structural changes of... more
Bovine beta-lactoglobulin (beta-LG) in vivo (in milks) has been found in complexes with lipids such as butyric and oleic acids. To elucidate the still unknown structure-function relationship in this protein, the structural changes of beta-lactoglobulin variant A (beta-LG A) in the presence of anionic surfactant such as sodium n-dodecyl sulfate (SDS) and in the presence of nonionic surfactant such as Triton X-100 have been investigated. Subsequently, the retinol binding by beta-LG has been investigated in the presence of various amounts of these surfactants as its binding indicator. The results of UV-vis and fluorescence studies show a higher denaturating effect of SDS at acid pH that can be due to greater positive charges of beta-LG at this pH indicating also the nonspecific hydrophobic interactions of Triton X-100 with beta-LG at all studied pHs. Isothermal titration calorimetry (ITC) measurements indicate the endothermic nature of beta-LG/SDS interactions and the exothermic nature of Triton X-100/beta-LG interactions. The analysis of the binding data demonstrates the absence of considerable changes in retinol binding properties of beta-LG in the presence of various amounts of these surfactants. This implies that surfactant binding does not change the conformation of beta-LG in the regions defining the retinol-binding site.
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beta-Lactoglobulin (beta-LG) is one of the... more
beta-Lactoglobulin (beta-LG) is one of the cow's major milk proteins and the most abundant whey protein. This globular protein of about 18 kDa is folded, forming a beta-barrel (or calyx) structure. This structure is stabilized by two disulfide bonds and can be altered by heating above 65 degrees C. beta-LG is also one of the major allergens in milk. Heating is one of the most common technologic treatments applied during many milk transformations. During heating in the presence of reducing sugars, beta-LG is also submitted to the Maillard reaction, which at the first stage consists of the covalent fixation of sugars on the epsilon-amino groups of lysyl residues. The following steps are condensation and polymerization reactions leading to the formation of melanoidins (brown pigments). Despite the frequency of use of heating during milk transformation, the effects of heat-induced denaturation and of glycation of beta-LG on its recognition by IgE from cow's milk allergy (CMA) patients are not fully understood. The objectives of our work were to evaluate the effect of heat-induced denaturation of bovine beta-LG on binding of IgE from CMA patients and to determine the effect of moderate glycation on the degree of recognition by IgE. We showed that heat-induced denaturation (loss of tertiary and secondary structures) of beta-LG is associated with weaker binding of IgE from CMA patients. It was also shown that moderate glycation of beta-LG in early stages of Maillard reaction has only a small effect on its recognition by IgE, whereas a high degree of glycation has a clear "masking" effect on the recognition of epitopes. This demonstrates the importance of epsilon-amino groups of lysines in the definition of epitopes recognized by IgE.
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The changes of structure and ligand binding properties of beta-LG B have been studied by fluorescence and circular dichroism spectroscopy in ethanolic solutions. Fluorescence measurements of retinol/beta-LG interactions at 480 nm in... more
The changes of structure and ligand binding properties of beta-LG B have been studied by fluorescence and circular dichroism spectroscopy in ethanolic solutions. Fluorescence measurements of retinol/beta-LG interactions at 480 nm in various ethanol concentrations show that the maximal fluorescence intensity induced by this interaction between retinol and beta-LG is observed around 20% v/v of ethanol. It is reduced to zero at 40% and 50% of ethanol. These results suggest that there are two distinct structural changes in beta-LG occurring between 20% and 30% and around 40% of ethanol. The first transition, which increases affinity and the apparent number of binding sites for retinol, may be related or similar to the Tanford transition. The strong quenching of retinol emission at 480 nm in 40% of ethanol indicates the radical transformation of beta-LG tertiary structure and the release of retinol. CD spectra at the aromatic region show that secondary and tertiary structures of beta-LG are not significantly affected between 0% and 20% of ethanol. In 30% of ethanol, beta-sheet percentage of beta-LG decreases with respect to native beta-LG (from 55% to 46%). beta-Sheet percentage in beta-LG increases in 40% and 50% alcohol (51% and 53%) relative to 30% of ethanol, which also indicates the strong rearrangement of the secondary structure of beta-LG, while its tertiary structure and beta-LG interactions are radically changed.
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Research Interests:
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This result has been interpreted on basis of the chemical structure of porphyrins and electronegativity of their central metal. The values of calculated binding constants represent the less affinity of TBzPyP and its metal derivatives to... more
This result has been interpreted on basis of the chemical structure of porphyrins and electronegativity of their central metal. The values of calculated binding constants represent the less affinity of TBzPyP and its metal derivatives to DNA in comparison with meso-...
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... 17 LD Kwiatkowsky and RW Noble, J.Boii.Chem., 257,8891(1982). 18 KO Okonjo, A. Taiwo, M.Balogun and OB Ekisola, Biochim.Biophys.Acta, 576,30 (1979). 19 MF Perutz, Nature, 288,734 (1970). 20 KJ Laidler and BF Peterman, Methods Enzymol,... more
... 17 LD Kwiatkowsky and RW Noble, J.Boii.Chem., 257,8891(1982). 18 KO Okonjo, A. Taiwo, M.Balogun and OB Ekisola, Biochim.Biophys.Acta, 576,30 (1979). 19 MF Perutz, Nature, 288,734 (1970). 20 KJ Laidler and BF Peterman, Methods Enzymol, 63,234 (1979). ...
Research Interests: Chemical Engineering, Thermodynamics, Biomedical Engineering, Fluorescence Spectroscopy, Electrochemistry, and 15 moreKinetics, Magnetic Resonance Spectroscopy, Cellulose, Adsorption, Cellulase, Gibbs Free Energy, Aspergillus niger, Enzyme, Surface Active Agents, Electrodes, Quaternary Ammonium Compounds, Cations, Hydrolysis, Hydrogen-Ion Concentration, and Binding Site
The interaction of cetyl trimethylammonium bromide (CTAB) with alpha-amylase from Bacillus subtilis was investigated at 25 degrees C and various experimental conditions, such as pH, ionic strength and urea concentration. The binding data... more
The interaction of cetyl trimethylammonium bromide (CTAB) with alpha-amylase from Bacillus subtilis was investigated at 25 degrees C and various experimental conditions, such as pH, ionic strength and urea concentration. The binding data were measured using CTAB-membrane selective electrodes as a simple, fast, cheap and accurate method. The obtained binding isotherms were analyzed using Wyman binding potential concept. The results represent the highest binding affinity at 10(-3) M of NaBr respect to other salt concentrations. The less binding affinity at pH 9.7 with respect to pH 6.5 is related to increasing of protein self aggregation with pH. The binding data analysis at various urea concentrations also shows that the predominate unfolding of alpha-amylase occurred in the urea concentration range of 3-5 M.
Research Interests: Chemical Engineering, Thermodynamics, Biomedical Engineering, Protein Folding, Data Analysis, and 14 morePotentiometry, Temperature, Urea, Bacillus subtilis, Denaturation, Surface Active Agents, Electrodes, Ionic Strength, Protein Binding, Biocompatible Materials, Hydrogen-Ion Concentration, Protein Denaturation, Ions, and Binding affinity
The binding of a homologous series of n-alkyltrimethyl ammonium bromides with Jack bean urease (JBU) have been studied previously. It has been suggested that both electrostatic and hydrophobic interactions are involved in the formation of... more
The binding of a homologous series of n-alkyltrimethyl ammonium bromides with Jack bean urease (JBU) have been studied previously. It has been suggested that both electrostatic and hydrophobic interactions are involved in the formation of surfactant-protein complexes, but there is not any quantities analyzing method for resolution of their contributions in the process. In the present study, at first, the intrinsic Gibbs free energy of binding, DeltaG(b,nu), has been calculated for these systems and the trend of variation for both binding sets have been interpreted on basis of cooperativity and hydrophobicity of surfactants. Subsequently, a novel approach has been introduced for estimation of electrostatic and hydrophobic interactions in DeltaG(b,nu), by considering of this fact that DeltaG(b,nu) is the summation of electrostatic, DeltaG(b,nu)(ele), and hydrophobic, DeltaG(b,nu)(hyd), parts and considering this fact that just DeltaG(b,nu)(hyd) is a function of hydrocarbon tail length of surfactant (C(n)). The results represents the higher positive rule of electrostatic interactions in binding affinity of first set and inhibiting rule of this interaction in the second binding set. The predominate driving force in the second binding set is entropy statistical effect, which arises from numerous number of binding sites in this set. A binding mechanism on basis of structural changes in JBU due to its interaction with cationic surfactants has also been proposed.
Research Interests: Chemical Engineering, Biomedical Engineering, Entropy, Hydrophobic Interactions, Animals, and 15 moreGibbs Free Energy, Structural Change, Free Energy, SURFACTANT PROTEIN A, Surface Active Agents, Electrostatic Interactions, Quaternary Ammonium Compounds, Cations, Binding Site, Static Electricity, Binding affinity, Driving force, Statistics as Topic, binding sites, and Electrostatic interaction
Research Interests: Chemical Engineering, Biomedical Engineering, Kinetics, Circular Dichroism, Animals, and 15 moreARG, Structural Change, Cattle, Protein Secondary Structure Prediction, Fluorimetry, Isothermal Titration Calorimetry, Calorimetry, Oleic Acid, Quaternary Ammonium Compounds, Structure activity Relationship, Quantum Yield, Protein Binding, Cations, Binding Site, and Conformational Change
Research Interests: Chemical Engineering, Thermodynamics, Biomedical Engineering, Membranes, Electrochemistry, and 14 moreAbsorption spectroscopy, Gibbs Free Energy, Temperature, Urea, Aspergillus niger, Enzyme, Spectrum analysis, Enzyme activity, Electrodes, Ionic Strength, Protein Binding, Hydrogen-Ion Concentration, Protein Denaturation, and Glucose Oxidase
Research Interests: Chemical Engineering, Biomedical Engineering, Fluorescence Spectroscopy, Fluorescence, Humans, and 13 morePotentiometry, Ligand Binding, Surface Properties, Sensitivity and Specificity, Cooperative Behavior, Binding Site, Conformational Change, Human Serum Albumin (HSA), Binding affinity, Serum albumin, binding sites, Electrostatic interaction, and Human serum albumin
The parent and nanosized starch, and lipid encapsulated K6[SiW11O39Co(H2O)]·nH2O (abbreviated as SEP, LEP and SiW11Co, respectively), as potent antitumor candidates, were synthesized and characterized by FT-IR spectroscopy, ICP, TG... more
The parent and nanosized starch, and lipid encapsulated K6[SiW11O39Co(H2O)]·nH2O (abbreviated as SEP, LEP and SiW11Co, respectively), as potent antitumor candidates, were synthesized and characterized by FT-IR spectroscopy, ICP, TG analysis, SEM and TEM images. The results show that the SiW11Co retains its parent structure after encapsulation by starch and lipid nanoparticles. Antitumor activity tests of SiW11Co and its encapsulated forms were carried out on two types of human cancer cells, MCF-7 and HEK-293 by MTT method. The encapsulated forms exhibited the higher antitumor activity compared to the parent SiW11Co. However, this observed enhancement for the lipid encapsulated form is more than the starch counterpart, which can be related to its smaller size. These results showed that these compounds can be novel antitumor candidates. The calf thymus DNA (abbreviated as ctDNA) binding ability of SiW11Co was also investigated, using UV-Vis absorption spectroscopy, fluorescence quenching and fluorescence Scatchard plots. Absorption spectra tracing reveal 10% hyperchromism for SiW11Co. The values of 1.8×10(4) and 1.2×10(4)M(-1) were obtained for association binding constant of SiW11Co to ctDNA at R⩾1 and R<1, respectively (R is defined as the mole ratio of SiW11Co to ctDNA). It was shown that the interaction of SiW11Co with ctDNA depended on the R values. The obtained results of absorption titration rejected the intercalating binding mode and suggest the groove or outside stacking binding for SiW11Co. These results were authenticated by fluorescence quenching experiments and scatchard plots.
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Research Interests:
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Abstract The present study evaluates the binding of cetylpyridinium chloride (CPC) with cellulase in various experimental conditions using potentiometric, fluorescence spectroscopy and turbidimetric tech-niques. The analysis of binding... more
Abstract The present study evaluates the binding of cetylpyridinium chloride (CPC) with cellulase in various experimental conditions using potentiometric, fluorescence spectroscopy and turbidimetric tech-niques. The analysis of binding curves revealed the existence of two sets of binding ...
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The interactions of bisdemethoxycurcumin (BDMC) as a bioactive constituent of turmeric and diacetylbisdemethoxycurcumin (DABC) as a novel synthetic derivative of curcumin with human serum albumin (HSA) have been investigated by... more
The interactions of bisdemethoxycurcumin (BDMC) as a bioactive constituent of turmeric and diacetylbisdemethoxycurcumin (DABC) as a novel synthetic derivative of curcumin with human serum albumin (HSA) have been investigated by fluorescence and circular dichroism (CD) spectroscopy. The binding parameters, including the number of substantive binding sites and the binding constants, have been estimated from the analysis of fluorescence measurements. The estimated binding parameters indicated that BDMC has higher affinity than DABC to bind HSA, suggesting the essential role of the phenolic OH groups of BDMC, which are acetylated in DABC. It was found that the binding site for BDMC and DABC is located in the vicinity of Trp-214 in subdomain IIA, which is the same as binding site for curcumin (CUR). The minor changes on the far-UV circular dichroism spectra resulted in partial changes in the calculated secondary structure contents of HSA. The negligible alteration in the secondary struct...
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The binding of dodecyltrimethylammonium bromide (DTAB) with -amylase was investigated under various ex-perimental conditions, such as pH, ionic strength, urea and protein concentration at 25 C using surfactant membrane-selective... more
The binding of dodecyltrimethylammonium bromide (DTAB) with -amylase was investigated under various ex-perimental conditions, such as pH, ionic strength, urea and protein concentration at 25 C using surfactant membrane-selective electrodes as a fast and accurate method. ...
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2232 Bull. Chem. Soc. Jpn., 69, No. 8 (1996) 400r Binding Data Analysis of the Protein -3-5 -3 -2-5 Log[DTAB]f Fig. 1. Binding isotherms for the interaction of DTAB with bovine hemoglobin at pH = 6.4. (Л) 300 K, (□) 310 K. binding... more
2232 Bull. Chem. Soc. Jpn., 69, No. 8 (1996) 400r Binding Data Analysis of the Protein -3-5 -3 -2-5 Log[DTAB]f Fig. 1. Binding isotherms for the interaction of DTAB with bovine hemoglobin at pH = 6.4. (Л) 300 K, (□) 310 K. binding potential П is calculated from the area under ...
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β-Lactoglobulin (β-LG) is a lipocalin, which is the major whey protein of... more
β-Lactoglobulin (β-LG) is a lipocalin, which is the major whey protein of cow's milk and the milk of other mammals. However, it is absent from human milk. The biological function of β-LG is not clear, but its potential role in carrying fatty acids through the digestive tract has been suggested. β-LG has been found in complexes with lipids such as butyric and oleic acids and has a high affinity for a wide variety of compounds. Serotonin (5-hydroxytryptamine, 5-HT), an important compound found in animals and plants, has various functions, including the regulation of mood, appetite, sleep, muscle contraction, and some cognitive functions such as memory and learning. In this study, the interaction of serotonin and one of its derivatives, arachidonyl serotonin (AA-5HT), with β-LG was investigated using circular dichroism (CD) and fluorescence intensity measurements. These two ligands interact with β-LG forming equimolar complexes. The binding constant for the serotonin/β-LG interaction is between 10⁵ and 10⁶ M(-1) , whereas for the AA-5HT/β-LG complex it is between 10⁴ and 10⁵ M(-1) as determined by measurements of either protein or ligand fluorescence. The observed binding affinities were higher in hydroethanolic media (25% EtOH). The interactions between serotonin/β-LG and AA-5HT/β-LG may compete with self-association (micellization) of both the ligand and the protein. According to far- and near-UV CD results, these ligands have no apparent influence on β-LG secondary structure, however they partially destabilize its tertiary structure. Their binding by β-LG may be one of the peripheral mechanisms of the regulation of the content of serotonin and its derivatives in the bowel of milk-fed animals.
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Research Interests: Porphyrins, Biological Sciences, Humans, Circular Dichroism, Ultraviolet, and 15 morePhysical sciences, Spectrophotometry, Tryptophan, Steady state, CHEMICAL SCIENCES, Secondary Structure, Time Factors, Energy Transfer, Aqueous Solution, Protein Binding, Long Distance, Serum albumin, Fluorescence quenching, Electrostatic interaction, and Human serum albumin
In the present study, the binding properties of naringenin (NG) to β-lactoglobulin (BLG) were explored using spectrofluorimetric and molecular modeling techniques. Analysis of spectrofluorimetric titration data represented the formation... more
In the present study, the binding properties of naringenin (NG) to β-lactoglobulin (BLG) were explored using spectrofluorimetric and molecular modeling techniques. Analysis of spectrofluorimetric titration data represented the formation of 1:1 complex, significant binding affinity, negative values of entropy and enthalpy changes and the essential role of hydrogen bonding and van der Waals interactions in binding of NG to BLG. The value of determined Förster's distance represents the static mechanism for quenching of BLG by NG. The results of fluorescence competitive binding experiments characterize the location of NG binding site in the outer surface of BLG. Molecular docking study showed that NG binds in the outer surface site of BLG which is accompanied with three hydrogen bonds. The support of molecular docking results by biochemical fluorescence experiments confirms the validity of docking calculation. Analysis of molecular dynamics results indicated that NG can interact with BLG without affecting the secondary structure of protein.
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... Zohreh Saadati1, Mehran Aghaie2, * and AK Bordbar 3 ... of nine antiparallel β -strands shaped into a calyx, a three-turn α-helix, and four short 310 helical fragments located in the N-terminal, AB, GH, and C-terminal loops [3, 4]. In... more
... Zohreh Saadati1, Mehran Aghaie2, * and AK Bordbar 3 ... of nine antiparallel β -strands shaped into a calyx, a three-turn α-helix, and four short 310 helical fragments located in the N-terminal, AB, GH, and C-terminal loops [3, 4]. In 1955, it was found that bovine BLG existed in two ...
Research Interests: Thermodynamics, Protein Folding, Humans, Temperature, Phase transition, and 14 moreTemperature Dependence, Heat Capacity, Secondary Structure, Surface Active Agents, Isothermal Titration Calorimetry, Protein Conformation, Energy Transfer, Protein Binding, Cations, Human Serum Albumin (HSA), Biochemistry and cell biology, Serum albumin, binding sites, and Human serum albumin
Chemical synthetic method in synthesizing silver nanoparticle was quite expensive, toxic and flammable. In order to enhance green technology, we develop a simple biological method for the green synthesis of silver nanoparticles using two... more
Chemical synthetic method in synthesizing silver nanoparticle was quite expensive, toxic and flammable. In order to enhance green technology, we develop a simple biological method for the green synthesis of silver nanoparticles using two lichens species, Parmotrema praesorediosum and Ramalina dumeticola. Silver nanoparticles were characterized using UV-Vis absorption spectroscopy and TEM. Within 72 hours reaction time, absorption spectra of silver nanoparticles formed in R. dumeticola and P. praesorediosum has absorbance peak at 407 nm and 423 nm, respectively. TEM analysis showed the average size of 20 nm of silver nanoparticles obtained in R. dumeticola and the average size of 42 nm of silver nanoparticles obtained in P. praesorediosum. These two lichens species are able to synthesize silver nanoparticles through green chemistry method, which are environmental friendly and cost effective. This is for the first time that any species of lichens was used for the synthesis of silver n...
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Abstract The effect of temperature (20-40 ◦ C) on the interaction between human serum albumin (HSA) and cetylpyridinium chloride (CPC) as a cationic surfactant was studied at physiological conditions (50 mM HEPES buffer, pH 7.4 and 160... more
Abstract The effect of temperature (20-40 ◦ C) on the interaction between human serum albumin (HSA) and cetylpyridinium chloride (CPC) as a cationic surfactant was studied at physiological conditions (50 mM HEPES buffer, pH 7.4 and 160 mM NaCl) using isothermal titration ...
Abstract: - The physicochemical properties of Ni (II) sodium tetra sulfunated phthalocyanine, NiPcTS, were investigated at different experimental conditions such as various concentrations of NiPc and ionic strength in10mM phosphate... more
Abstract: - The physicochemical properties of Ni (II) sodium tetra sulfunated phthalocyanine, NiPcTS, were investigated at different experimental conditions such as various concentrations of NiPc and ionic strength in10mM phosphate buffer, pH 7.4 at 25°C. The results show the ...
The interaction of cetyl trimethylammonium bromide (CTAB) with α-amylase from Bacillus subtilis was investigated at 25 °C and various experimental conditions, such as pH, ionic strength and urea concentration. The binding data were... more
The interaction of cetyl trimethylammonium bromide (CTAB) with α-amylase from Bacillus subtilis was investigated at 25 °C and various experimental conditions, such as pH, ionic strength and urea concentration. The binding data were measured using CTAB-membrane selective ...