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While the antigenic specificity and pathogenic relevance of immunologic reactivity to gluten in celiac disease have been extensively researched, the immune response to nongluten proteins of wheat has not been characterized. We aimed to... more
While the antigenic specificity and pathogenic relevance of immunologic reactivity to gluten in celiac disease have been extensively researched, the immune response to nongluten proteins of wheat has not been characterized. We aimed to investigate the level and molecular specificity of antibody response to wheat nongluten proteins in celiac disease. Serum samples from patients and controls were screened for IgG and IgA antibody reactivity to a nongluten protein extract from the wheat cultivar Triticum aestivum Butte 86. Antibodies were further analyzed for reactivity to specific nongluten proteins by two-dimensional gel electrophoresis and immunoblotting. Immunoreactive molecules were identified by tandem mass spectrometry. Compared with healthy controls, patients exhibited significantly higher levels of antibody reactivity to nongluten proteins. The main immunoreactive nongluten antibody target proteins were identified as serpins, purinins, α-amylase/protease inhibitors, globulins,...
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ABSTRACT A chymotrypsin-like protease has been prepared from the mouse P815Y mast-cell tumor. It is similar in most respects to the first such enzyme purified from the normal peritoneal mast cells of the rat. It, too, has a molecular... more
ABSTRACT A chymotrypsin-like protease has been prepared from the mouse P815Y mast-cell tumor. It is similar in most respects to the first such enzyme purified from the normal peritoneal mast cells of the rat. It, too, has a molecular weight (estimated by gel filtration) of about 25 000. The apparent molecular weight is lower, unless high salt concentrations are used to overcome affinity of this enzyme for the dextran or polyamide gel columns.The binding of indole, and the binding of potato chymotrypsin inhibitor I, are characteristically strong. Specific alkylations and phosphorylation suggest a serine-histidine active center system. The protein is basic, with strong affinity for the heparin of the mast cell granule. High K+ concentrations (>1 M), rather than Na+, are needed to displace fully the enzyme from heparin in solution.A trypsin-like enzyme is also prominent in the mouse (but not the rat) cells. The trypsin-like enzyme has a specificity and active center reactivity characteristic of pancreatic trypsin, and a molecular weight, estimated by gel filtration, of about 35 000.
Research Interests: Electron Microscopy, Kinetics, Mast Cells, Biological Sciences, Methods, and 26 moreHeparin, Mice, Animals, Male, Physical sciences, Cell Fractionation, Trypsin, Gels, Cell nucleus, Electrophoresis, Rats, Protease Inhibitors, Tritium, Arginine, Alkylation, Molecular weight, Somatic Cell Count, Toluene, Protein Binding, Esters, Hydrogen-Ion Concentration, Potassium Chloride, Histidine, Peritoneal Cavity, Tyrosine, and Chymotrypsin
A pseudopeptide analog of the active core of the leucokinin insect neuropeptide family was synthesized and found to retain myotropic activity. No reports of active pseudopeptide analogs of an insect or other invertebrate neuropeptide have... more
A pseudopeptide analog of the active core of the leucokinin insect neuropeptide family was synthesized and found to retain myotropic activity. No reports of active pseudopeptide analogs of an insect or other invertebrate neuropeptide have previously appeared in the literature. The pseudopeptide (Phe psi [CH2-NH] Phe-Ser-Trp-Gly-NH2) contains a reduced-amide linkage between the two N-terminal Phe residues. Unlike its amide-bond containing counterpart, the activity of the pseudopeptide was not destroyed upon exposure to aminopeptidase M.
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While tandem mass spectrometry (MS/MS) is routinely used to identify proteins from complex mixtures, certain types of proteins present unique challenges for MS/MS analyses. The major wheat gluten proteins, gliadins and glutenins, are... more
While tandem mass spectrometry (MS/MS) is routinely used to identify proteins from complex mixtures, certain types of proteins present unique challenges for MS/MS analyses. The major wheat gluten proteins, gliadins and glutenins, are particularly difficult to distinguish by MS/MS. Each of these groups contains many individual proteins with similar sequences that include repetitive motifs rich in proline and glutamine. These proteins have few cleavable tryptic sites, often resulting in only one or two tryptic peptides that may not provide sufficient information for identification. Additionally, there are less than 14,000 complete protein sequences from wheat in the current NCBInr release. In this paper, MS/MS methods were optimized for the identification of the wheat gluten proteins. Chymotrypsin and thermolysin as well as trypsin were used to digest the proteins and the collision energy was adjusted to improve fragmentation of chymotryptic and thermolytic peptides. Specialized databases were constructed that included protein sequences derived from contigs from several assemblies of wheat expressed sequence tags (ESTs), including contigs assembled from ESTs of the cultivar under study. Two different search algorithms were used to interrogate the database and the results were analyzed and displayed using a commercially available software package (Scaffold). We examined the effect of protein database content and size on the false discovery rate. We found that as database size increased above 30,000 sequences there was a decrease in the number of proteins identified. Also, the type of decoy database influenced the number of proteins identified. Using three enzymes, two search algorithms and a specialized database allowed us to greatly increase the number of detected peptides and distinguish proteins within each gluten protein group.
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Research Interests: Technology, Mass Spectrometry, Polyploidy, Biological Sciences, Gliadin, and 9 moreSodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis, High Performance Liquid Chromatography, High Pressure Liquid Chromatography, Protein Sequence Analysis, Rye, Amino Acid Sequence, Polyacrylamide Gel Electrophoresis, Triticum, and Triticum aestivum L.
Research Interests: Technology, Molecular Evolution, Mass Spectrometry, Biological Sciences, Maize, and 10 moreSeed Development, Tandem Mass Spectrometry, Poaceae, Liquid Chromatography / Electrospray Ionization Mass Spectrometry, Seeds, Model System, SIGNAL PEPTIDE, Amino Acid Sequence, Gene Family, and PLANT PROTEINS
Research Interests: Genetics, Mass Spectrometry, Proteomics, Protein synthesis, Cell Division, and 15 moreSignal Transduction, Biological Sciences, Protein Turnover, Nitrogen, Nitrogen metabolism, Lipid metabolism, Germination, Seeds, Carbohydrate metabolism, Two-Dimensional Gel Electrophoresis, Triticum, Two dimensional Gel Electrophoresis, Proteome, PLANT PROTEINS, and Triticum aestivum L.
Research Interests: Proteomics, Biological Sciences, Sequence alignment, Pollen, Tandem Mass Spectrometry, and 8 moreArabidopsis, Liquid Chromatography / Electrospray Ionization Mass Spectrometry, Two-Dimensional Gel Electrophoresis, Amino Acid Sequence, Cell Wall, Pollen Tube Growth, Two dimensional Gel Electrophoresis, and Proteome
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Research Interests: Protein Folding, Photosynthesis, Proteomics, Starch, Multidisciplinary, and 15 moreLipids, Oxidoreductases, Membrane transport, Affinity chromatography, Protein Function, Amino Acids, Glucose Transport, Thioredoxin, Seeds, Redox Regulation, Amino Acid Profile, Triticum, PLANT PROTEINS, Nucleotides, and Thioredoxin reductase
Thioredoxin (Trx), a small redox protein, controls multiple processes in eukaryotes and bacteria by changing the thiol redox status of selected proteins. The function of Trx in archaea is, however, unexplored. To help fill this gap, we... more
Thioredoxin (Trx), a small redox protein, controls multiple processes in eukaryotes and bacteria by changing the thiol redox status of selected proteins. The function of Trx in archaea is, however, unexplored. To help fill this gap, we have investigated this aspect in methanarchaea--strict anaerobes that produce methane, a fuel and greenhouse gas. Bioinformatic analyses suggested that Trx is nearly universal in methanogens. Ancient methanogens that produce methane almost exclusively from H2 plus CO2 carried approximately two Trx homologs, whereas nutritionally versatile members possessed four to eight. Due to its simplicity, we studied the Trx system of Methanocaldococcus jannaschii--a deeply rooted hyperthermophilic methanogen growing only on H2 plus CO2. The organism carried two Trx homologs, canonical Trx1 that reduced insulin and accepted electrons from Escherichia coli thioredoxin reductase and atypical Trx2. Proteomic analyses with air-oxidized extracts treated with reduced Trx1 revealed 152 potential targets representing a range of processes--including methanogenesis, biosynthesis, transcription, translation, and oxidative response. In enzyme assays, Trx1 activated two selected targets following partial deactivation by O2, validating proteomics observations: methylenetetrahydromethanopterin dehydrogenase, a methanogenesis enzyme, and sulfite reductase, a detoxification enzyme. The results suggest that Trx assists methanogens in combating oxidative stress and synchronizing metabolic activities with availability of reductant, making it a critical factor in the global carbon cycle and methane emission. Because methanogenesis developed before the oxygenation of Earth, it seems possible that Trx functioned originally in metabolic regulation independently of O2, thus raising the question whether a complex biological system of this type evolved at least 2.5 billion years ago.
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Mitochondria contain thioredoxin (Trx), a regulatory disulfide protein, and an associated flavoenzyme, NADP/Trx reductase, which provide a link to NADPH in the organelle. Unlike animal and yeast counterparts, the function of Trx in plant... more
Mitochondria contain thioredoxin (Trx), a regulatory disulfide protein, and an associated flavoenzyme, NADP/Trx reductase, which provide a link to NADPH in the organelle. Unlike animal and yeast counterparts, the function of Trx in plant mitochondria is largely unknown. Accordingly, we have applied recently devised proteomic approaches to identify soluble Trx-linked proteins in mitochondria isolated from photosynthetic (pea and spinach leaves) and heterotrophic (potato tubers) sources. Application of the mitochondrial extracts to mutant Trx affinity columns in conjunction with proteomics led to the identification of 50 potential Trx-linked proteins functional in 12 processes: photorespiration, citric acid cycle and associated reactions, lipid metabolism, electron transport, ATP synthesis/transformation, membrane transport, translation, protein assembly/folding, nitrogen metabolism, sulfur metabolism, hormone synthesis, and stress-related reactions. Almost all of these targets were also identified by a fluorescent gel electrophoresis procedure in which reduction by Trx can be observed directly. In some cases, the processes targeted by Trx depended on the source of the mitochondria. The results support the view that Trx acts as a sensor and enables mitochondria to adjust key reactions in accord with prevailing redox state. These and earlier findings further suggest that, by sensing redox in chloroplasts and mitochondria, Trx enables the two organelles of photosynthetic tissues to communicate by means of a network of transportable metabolites such as dihydroxyacetone phosphate, malate, and glycolate. In this way, light absorbed and processed by means of chlorophyll can be perceived and function in regulating fundamental mitochondrial processes akin to its mode of action in chloroplasts.
Research Interests: Mitochondria, Apoptosis, Multidisciplinary, Energy Metabolism, Enzymes, and 14 moreMembrane transport, Nitrogen metabolism, Lipid metabolism, Electron Transport, Affinity chromatography, Protein Function, Mode of action, Thioredoxin, Plant Mitochondria, Gel electrophoresis, Citric Acid, Recombinant Proteins, PLANT PROTEINS, and Oxidation-Reduction
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A KCl-soluble, albumin/globulin fraction of wheat (Triticum aestivum L.) starchy endosperm was further separated into a methanol-insoluble fraction that contained metabolic proteins and a methanol-soluble fraction that contained... more
A KCl-soluble, albumin/globulin fraction of wheat (Triticum aestivum L.) starchy endosperm was further separated into a methanol-insoluble fraction that contained metabolic proteins and a methanol-soluble fraction that contained "chloroform-methanol" or CM-like proteins. Reduction of the disulfide bonds of the CM proteins with thioredoxin or dithiothreitol altered their properties so that, like the metabolic proteins, they were insoluble in methanol. Glutathione had little effect, indicating dithiol specificity. Proteomic analysis of the CM protein fraction revealed the presence of isoforms of low molecular weight disulfide proteins (alpha-amylase, alpha-amylase/trypsin and WCI proteinase inhibitors, lipid transfer proteins, gamma-thionins), stress enzymes (Cu-Zn superoxide dismutase and peroxidase), storage proteins (alpha-, gamma- and omega-gliadins, low molecular weight glutenin subunits and globulins of the avenin N9 type), and a component of protein degradation (polyubiquitin). These findings support the view that, in addition to modifying activity and increasing protease sensitivity, reduction by thioredoxin alters protein solubility, thereby promoting processes of the grain starchy endosperm, notably the mobilization of reserves during germination and seedling development.
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Research Interests: Engineering, Mass Spectrometry, Triticum Aestivum, Gliadin, Sequential Extraction, and 13 moreFlour, Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis, Solubility, Agricultural, High Pressure Liquid Chromatography, CHEMICAL SCIENCES, Chemical Precipitation, Agricultural and Food Chemistry, Small samples, Triticum, PLANT PROTEINS, Protein Quality, and Wheat flour
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... The fruit were checked daily for firmness using a penetrometer (University of California FirmnessTester; Western Industrial Supply Co., San ... of Adventitious Proteins (4 June 2006) available from the Global Proteome Machine... more
... The fruit were checked daily for firmness using a penetrometer (University of California FirmnessTester; Western Industrial Supply Co., San ... of Adventitious Proteins (4 June 2006) available from the Global Proteome Machine Organization (ftp://ftp.thegpm.org/fasta/cRAP). ...