Amylase

The toxic effect of some extracts of the aerial parts of Ipomea carnea that collected from Sharkia Governorate, Egypt, against 4 th instar larvae of Spodoptera littoralis was evaluated under laboratory conditions. Based on LC 50 and LC 90 values, Ipomea Carnea extracts were recorded (24.622 and 164.947 ppm., respectively) for the most potent one (acetonic extract) followed by hexane (232.677 and 15377.590 ppm., respectively) and finally the alcoholic extract which doesn't reveal any toxicity until 5 days post treatment. Chloropyrifos insecticide gave (9.497 and 91.126 ppm, respectively) the chemical constituents of acetonic extract of the aerial part of I. carnea were determined using GC_MS analysis. The most active compounds were Palmatic (iso propyl-hexadecanoate), Silane, [[3.alpha.,5.alpha.,20R)-pregnane-3,20-diyl]bis(oxy)] bis (trimethyl-(cas)5.and Pederone, that recorded (44.025, 11.455 and 9.325%, respectively). On the other hand, the activity of carbohydrate hydrolyzing enzymes (amylase, invertase and trehalase) in S. littoralis larvae was generally increased as affected by all tested concentrations compare to larvae treated with acetone only that (97.46, 97.66 and 99.33%), respectively (LC 25) of I. carnea that caused 77.11% on trehalase enzyme.

Flavonoids are a group of polyphenols that provide health-promoting benefits upon consumption. However, poor bioavailability has been a major hurdle in their use as drugs or nutraceuticals. Low bioavailability has been associated with flavonoid interactions at various stages of the digestion, absorption and distribution process, which is strongly affected by their molecular structure. In this review, we use structure-activity/property relationship to discuss various flavonoid interactions with food matrices, digestive enzymes, intestinal transporters and blood proteins. This approach reveals specific bioactive properties of flavonoids in the gastrointestinal tract as well as various barriers for their bioavailability. In the last part of this review, we use these insights to determine the effect of different structural characteristics on the overall bioavailability of flavonoids. Such information is crucial when flavonoid or flavonoid derivatives are used as active ingredients in fo...

Biochemical changes in wheat grains stored at 10, 25 and 45 °C for six months were studied. A significant decrease in pH and an increase in titratable acidity was observed during storage of wheat grains at 25 °C and 45 °C. Moisture contents of wheat grains decreased by 15% at 25 °C and 26% at 45 °C during six months of storage. A significant decrease in water soluble amylose (20–28%) along with an increase in insoluble amylose contents (7.6–17%) were observed during storage at 25 and 45 °C. Amylase activity of the samples showed a decrease as the storage progressed. Total soluble sugars increased by 9% at 10 °C and 12% at 25 °C; a 37% decrease was observed after six months storage at 45 °C. Total available lysine decreased by 18.0% and 22.6% at 25 and 45 °C, respectively, after six months storage. In vitro protein digestibility of wheat grains decreased by 5.00% at 25 °C and 10.28% at 45 °C during six months of storage. However, no significant biochemical changes occurred during storage at 10 °C.

During the present studies, thirteen antagonistic compost inhabiting bacteria and fungi selected from in vitro studies against soil borne pathogens were evaluated for their amylase, cellulase and pectinase activities. Most of the antagonists showed the enzymatic activities. The antagonists were also inoculated in to the grass clippings to see their degradation abilities. All the antagonists showed the ability to degrade the grass clippings but with varied rate of degradation. The highest rate of degradation shown by Bacillus licheniformis and Aspergillus fumigatus followed by

We have studied experimentally the enzymatic hydrolysis of soluble starch with a commercial α-amylase from Bacillus licheniformis (commercial enzyme Termamyl 300 L Type DX) at pH 7.5 within the temperature range of 60–75 °C. To follow the reaction we applied a procedure based on the iodometric method of measuring α-amylase activity. We found for each of the temperatures studied that at the same treatment intensity the different enzyme concentrations and reaction times assayed gave practically the same conversion values, whereas these values were altered according to the length of time the enzyme solutions were previously kept at reaction temperature. Therefore, the thermal denaturation of the enzyme can be fitted to a second-order kinetic. We have established a way of calculating the deactivation constant for each temperature both for the experiments made with different waiting times before the reaction and for those with different treatment intensity. Finally, we fitted the thermal-deactivation constant against temperature according to Arrhenius’ equation, obtaining an activation energy of 172 kJ/mol.

An ideal laboratory test in the evaluation of a patient with acute pancreatitis (AP) should, in addition to accurately establishing the diagnosis of AP, provide early assessment of its severity and identify the etiology. None of the tests available today meet all these criteria, and presently there is no biochemical test that can be considered the "gold standard" for the diagnosis and assessment of severity of AP. In the diagnosis of AP, serum amylase and lipase remain important tests. Advantages of amylase estimation are its technical simplicity, easy availability, and high sensitivity. However, its greatest disadvantage is its low specificity. A normal amylase would usually exclude the diagnosis of AP, with the exception of AP secondary to hyperlipidemia, acute exacerbation of chronic pancreatitis, and when the estimation of amylase is delayed in the course of the disease. The major advantage of lipase is an increased sensitivity in acute alcoholic pancreatitis and in pa...

Galanin inhibits pancreatic amylase secretion from mouse lobules induced by physiological concentrations of caerulein via an insulin-dependent mechanism. We aimed to determine the effect and elucidate the mechanism of action of exogenous galanin on pancreatic amylase secretion induced by supramaximal concentrations of caerulein. Amylase secretion from isolated murine pancreatic lobules was measured. Lobules were coincubated with galanin (10−12–10−7 M) and caerulein (10−7 M). Lobules were preincubated with atropine (10−5 M), tetrodotoxin (10−5 M), diazoxide (10−7 M), or the galanin antagonist galantide (10−12–10−7 M) for 30 min followed by incubation with caerulein alone, or combined with galanin (10−12 M). Lobules were also coincubated with combinations of galanin (10−12 M), caerulein, octreotide (10−12–10−7 M) or cyclo-(7-aminoheptanoyl-Phe-D-Trp-Lys-Thr[BZL]), a somatostatin receptor antagonist (10−9 M). Amylase secretion was expressed as percent of total lobular amylase. Caerulei...

Alpha amylase (E.C. 3.2.1.1) is one of the most important starch-degrading enzymes and widely applied in pharmaceutical, food, feed, detergent, textile and bio refinery industries. The present work was focused on optimization of -amylase production using the bacteria strain Bacillus amyloliquefaciens in submerged cultivation system. The results showed that, the optimal soluble starch concentration for maximal enzyme production of 1950 kat.L-1 was 20 g.L-1. Compared to shake flask, bioreactor batch cultivation yielded higher volumetric enzyme production of 4125 kat.L-1 (about 1.84-folds higher than the value obtained in shake flask). In addition, fed-batch cultivation with two feeding strategies (constant feeding and increased feeding) was also designed to improve the production process. The maximal volumetric enzyme production of 8160 kat.L-1 was obtained in increased feeding strategy after 36 hours of cultivation. This value was almost 98 and 18% higher than the enzyme produced in batch and constant feeding fed-batch cultivations, respectively.

1) Dep. of Food Biotechnology, Faculty of Agricultural Sciences, Food Engineering and Environmental Protection, Lucian Blaga University of Sibiu, Romania 2) Dep. of Food Engineering, Faculty of Agricultural Sciences, Food Engineering and Environmental Protection, Lucian Blaga ...

Starch digestion begins in the mouth where it is hydrolysed into smaller polysaccharides by the enzyme salivary amylase.  Three salivary amylase genes (AMY1A,B & C) and a psuedogene (AMYP1) have been described and are located in tandem on the short arm of chromosome 1.  Polymorphic variation has been demonstrated in Caucasian populations in the form of the number of repeats of the AMY1 genes, as follows: (1A-1B-P1)n-1C. This variation results in differing levels salivary amylase enzyme production and, as a result, differences in the efficiency of starch digestion.  It is suggested that an increase in salivary gene copy number may be an adaptation to high starch diets as a result of the adoption of agriculture.  A reliable high-throughput PCR based method has been designed that utilises ABI GeneScan technology, to quantify AMY1 gene copy number and to type 6 microsatellite markers closely linked to the AMY gene cluster.  Data have been collected for 14 human populations, with different histories of cereal agriculture and levels of starch in the diet. Data have also been collected on AMY1 gene copy number in 5 common chimpanzees (Pan troglodytes). 

The AMY1 allele frequency difference (measured using FST)  between the two most extreme populations, the Mongolians and Saami, was not an outlier on a distribution of 11,024 SNPs from the human genome.  As the AMY1 locus does not appear to differ from the rest of the genome in terms of allele frequency difference between populations, genetic drift could not be ruled out as an explanation for the observed AMY1 allele frequency differences.  The chimpanzee data suggest that the most frequent allele (AMY1*H1) in humans may not be the ancestral allele, as all chimpanzee chromosomes tested carried the AMY1*H0 allele.  Furthermore, a powerful method for the analysis of intra-allelic variability at the AMY locus suggests that weak positive selection has occurred on the AMY*H1 allele. As a result, genetic drift could not be ruled out as an explanation for the observed AMY1 allele frequency difference among populations.

Alanine:glyoxylate aminotransferase (AGT) is an intermediary metabolic enzyme that is targeted to different organelles in different species.  Previous studies have shown that there is a clear relationship between the organellar distribution of AGT and diet.  Non-human primates show the herbivorous peroxisomal distribution of AGT.  In humans a point mutation and insertion deletion polymorphism have been associated with peroxisome-to-mitochondria AGT mis-targeting.  Data have been collected using a PCR/RFLP based method, in 11 human populations.  In a comparison with FST values from 11,024 SNP loci, 94.5% of SNPs had a lower FST than a comparison of AGT allele frequencies for Saami and Chinese.  This unusually high allele frequency difference between Chinese and Saami is consistent with the signature of positive selection driven by the unusually high meat content in the Saami diet.