Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The filamentous fungus, Aspergillus niger, efficiently converted cassava polysaccharides to mycelial mass, simple sugars, and acids during the course of its growth. A typical 70-ml culture broth containing 2% cassava polysaccharides yielded 0.38 g dry mycelial mass, 1.14 mmol reducing sugars, and 1.17 meq acids at the end of 42 h. About 70% of the initial total carbohydrate in the medium was degraded during the same period. The sugars and acids in the culture broths were analyzed by HPLC on a single Aminex HPX-87 column at 55 degrees C, using 0.013 N H2SO4 as the eluting solvent. Cassava polysaccharides were degraded to oligosaccharides, maltotriose, maltose, and glucose beyond the 20-h growth periods, with maltotriose emerging as the major simple sugar. The appearance of citric, malic, gluconic, succinic, and fumaric acids accounted mostly for the decreasing pH in the growth media. Formation of carbohydrate species in the culture broths was closely related to the biosynthesis and secretion of several carbohydrases by A. niger. The extracellular carbohydrases were separated and identified by chromatofocusing and polyacrylamide gel electrophoresis to be amyloglucosidase (EC 3.1.2.3), alpha-amylase (EC 3.2.1.1), and alpha-glucosidase (EC 3.2.1.20), respectively.
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PMID:Conversion of cassava starch to biomass, carbohydrates, and acids by Aspergillus niger. 649 May 84

Culture filtrates of Cladosporium resinae ATCC 20495 contain a mixture of enzymes able to convert starch and pullulan efficiently into D-glucose. Culture conditions for optimal production of the pullulan-degrading activity have been established. The amylolytic enzyme preparation was fractionated by ion-exchange and molecular-sieve chromatography, and shown to contain alpha-D-glucosidase, alpha-amylase, and two glucoamylases. The glucoamylases have been purified to homogeneity and their substrate specificities investigated. One of the glucoamylases (termed P) readily hydrolyses the (1 leads to 6)-alpha-D linkages in pullulan, amylopectin, isomaltose, panose, and 6(3)-alpha-D-glucosylmaltotriose. Each of the glucoamylases cleaves the (1 leads to 6)-alpha-D linkage in panose much more readily than that in isomaltose.
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PMID:Hydrolysis of alpha-D-glucans and alpha-D-gluco-oligosaccharides by Cladosporium resinae glucoamylases. 677 40

1. The levels of the brush-border enzymes sucrase (sucrose glucohydrolase, EC 3.2.1.48), isomaltase (oligo-1,6-glucosidase, EC 3.2.1.10), maltases 2 and 3 (glucoamylase, EC 3.2.1.3), lactase (beta-galactosidase, EC 3.2.1.23) and trehalase (EC 3.2.1.28) and adsorbed pancreatic alpha-amylase (EC 3.2.1.1) have been measured at twenty-one positions along the small intestines of eighty-four pigs of different ages ranging from 3 weeks to 4.5 years. The state of dilation of the intestine at the sampling points was noted. 2. The levels of sucrase and isomaltase increased with age throughout the age-range studied. Trehalase and the glucoamylases increased with age up to 200--300 d of age. Lactase decreased with age over the whole age range. 3. For the pigs above 10 weeks of age, the distribution pattern of the brush-border enzymes along the intestine did not change with age. Each enzyme had a characteristic distribution curve, with low values at the proximal and distal ends and a peak which was proximal in the instance of lactase and trehalase and approximately mid-way along the gut with sucrase, isomaltase and the glucoamylases. 4. The pattern of distribution of the brush-border enzymes altered with age in the piglets, but approached the adult pattern by 8 weeks. 5. Piglets weaned at 3 weeks had higher levels of sucrase, isomaltase and glucoamylases at 5 weeks than piglets left on the sow. At 8 weeks of age the piglets weaned at 3 weeks still had higher sucrase and isomaltase levels than those on the sow. 6. There was a very close correlation between the sucrase and isomaltase levels, and between the maltase 2 and maltase 3 levels in all the samples, and a fairly close correlation between all these four enzymes. 7. The level of alpha-amylase increased with age but showed no regular distribution pattern, its irregular fluctuations being related to the presence or absence of dilation of the intestine at the time of slaughter rather than to the position along the intestine.
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PMID:The level of distribution of carbohydrases in the small intestine mucosa of pigs from 3 weeks of age to maturity. 696 56

The effects of oat saponins (a mixture of avenacosides A and B) and dietary fibre (cellulose and guar gum) on the disaccharidase activities in the proximal small intestine of the rat were investigated. The influence of avenacosides A and B on the activity of disaccharidases and alpha-amylase (EC 3.2.1.1) was also studied in vitro. In vivo, oat diets with three avenacoside contents (negligible, normal and twice normal) were used. No significant differences in sucrase (EC 3.2.1.48), maltase (EC 3.2.1.20), trehalase (EC 3.2.1.28) and lactase (EC 3.2.1.21) activities were found between the oat groups after 19 d feeding. The rats that were given cellulose tended to have higher disaccharidase activities compared with the other groups. The avenacosides inhibited the lactase activity significantly in vitro while no or small effects on the other disaccharidases were found. In contrast, the in vitro hydrolysis of starch by alpha-amylase was increased in the presence of saponins, probably due to their detergent effect. Thus, the in vitro studies showed that the avenacosides could influence the enzyme activities. In vivo, these effects are probably minor due to the low avenacoside concentrations found in oats.
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PMID:Effect of oat saponins and different types of dietary fibre on the digestion of carbohydrates. 754 40

2-Deoxy-2,2-difluoroglycosides are a new class of mechanism-based inhibitors of alpha-glycosidases, which function via the accumulation of a stable difluoroglycosyl-enzyme intermediate. Two members of this new class of inhibitor have been synthesized and kinetic studies performed with their target glycosidases. Thus 2,4,6-trinitrophenyl 2-deoxy-2,2-difluoro-alpha-glucoside is shown to inactivate yeast alpha-glucosidase with a second order rate constant of ki/Ki = 0.25 min-1 mM-1. The equivalent difluoromaltoside inactivates human pancreatic alpha-amylase with ki/Ki = 0.0073 min-1 mM-1. Competitive inhibitors protect the enzyme against inactivation in each case, showing reaction to occur at the active site. A burst of release of one equivalent of trinitrophenolate observed upon inactivation of human pancreatic alpha-amylase proves the required 1:1 stoichiometry. These are the first mechanism-based inhibitors of this class to be described, and the first mechanism-based inhibitors of any sort for the medically important alpha-amylase. In addition to having potential as therapeutics, compounds of this class should prove useful in subsequent structural and mechanistic studies of these enzymes.
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PMID:Mechanism-based inhibition of yeast alpha-glucosidase and human pancreatic alpha-amylase by a new class of inhibitors. 2-Deoxy-2,2-difluoro-alpha-glycosides. 759 15

The influence of Amadori-compounds (fructosyl-, maltulosyl- and maltotriulosylglycin) on the activity of the enzymes alpha-glucosidase (from Saccharomyces cerevisiae), glucoamylase (from Aspergillus niger) and alpha-amylase (from porcine pancreas) was studied. Fructosylglycin was not hydrolyzed by all three enzymes. alpha-Glucosidase hydrolyzes maltulosylglycin 10 times slower than maltotriulosylglycin. Glucoamylase and alpha-amylase catalyze only the cleavage of maltotriulosylglycin to form glucose and maltulosylglycin. The activities of alpha-glucosidase and glucoamylase are inhibited through the Amadori-compounds fructosyl- and maltulosylglycin. These Amadori-compounds don't influence the activity of alpha-amylase. Electronic effects or interactions between the secondary amino function of Amadori-compounds and the carboxyl- or carboxylate groups of active centres could be responsible for such an inhibition.
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PMID:[The decomposition of Maillard reaction products by amylolytic enzymes. 1. Reversible inhibition of alpha- and glucoamylase and alpha-glucosidase by oligosaccharide Amidori compounds]. 783 34

The development of alpha-amylase and brush-border alpha-glucosidase inhibitors is reviewed. The mode of action as well as pharmacological and pharmacodynamic properties of selected inhibitors with special regard to the most thoroughly investigated alpha-glucosidase inhibitor acarbose are discussed. Inhibition of intestinal alpha-glucosidases delays the digestion of starch and sucrose, flattens the postprandial blood glucose excursions, and thus mimics the effects of dieting on hyperglycaemia, hyperinsulinaemia and hypertriglyceridaemia. Therefore, the mechanism of alpha-glucosidase inhibition represents the pharmacological optimization of the dietary principle of delayed carbohydrate absorption. In pre-clinical studies using diabetic animals the oral administration of acarbose improved the metabolic state and reduced the blood glucose area under the curve. As a consequence, the process of non-enzymatic glycation of proteins was retarded as indicated by reduced glycated haemoglobin, glomerular basement membranes or advanced glycation end-products (AGEs) in collagen. These improved biochemical parameters correlated with beneficial effects against the development of diabetic nephropathy and neuropathy. Thus, the treatment of diabetic animals with acarbose does not only improve the metabolic state but has also the potential to delay, or possibly prevent, the development of diabetic complications.
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PMID:Pharmacology of alpha-glucosidase inhibition. 800 24

We examined whether a modification of a starch into an alpha-amylase resistant form can lead to a reduction of postprandial glucose and insulin responses, and consequently to a change of lipid metabolism in liver and adipose tissue. For this purpose, a processed starch was prepared using a cornstarch (70% amylose and 30% amylopectin) and monoacylglycerol (monostearate; MS), forming monostearate-starch complex (MS-treated cornstarch). When we determined in vitro hydrolysis of MS-treated cornstarch using alpha-amylase and intestinal microvillar alpha-glucosidases, the glucose production rate of the MS-treated cornstarch was slower than the non-treated cornstarch. Measurement of a transmural potential difference (delta PD) evoked by the MS-treated cornstarch in everted rat jejunum showed that the absorption rate of glucose released from the MS-treated cornstarch was also remarkably slower than that from the non-treated cornstarch. The postprandial plasma insulin response to the MS-treated cornstarch was reduced, although plasma glucose response was unchanged. In a feeding study, two groups of five or six male Wistar-strain rats were fed defined diets containing 61.1% MS-treated cornstarch or 58.2% non-treated cornstarch ad libitum for 14 days. Food intakes during the period were similar between the two groups. Feeding the MS-treated cornstarch resulted in a significantly lower maltase activity in upper jejunum than did the non-treated cornstarch feeding. The activities of lipogenic enzymes--fatty acid synthetase (FAS), malic enzyme (ME), and glucose-6-phosphate dehydrogenase (G-6-PDH)--significantly decreased in epididymal adipose tissue of rats fed the MS-treated cornstarch. In the liver, FAS activity was lower in the MS-treated cornstarch group. The results indicated that MS-treated cornstarch was digested less rapidly, and lowered blood insulin response, consequently leading to a declined lipogenesis of adipose tissue and liver. This study suggests that the rate of intestinal hydrolysis of starch is an important determinant of metabolic responses such as glycemic and lipogenic responses to diets.
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PMID:Monostearoylglycerol-starch complex: its digestibility and effects on glycemic and lipogenic responses. 808 69

We cloned an alpha-glucosidase gene from thermophilic Bacillus sp. SAM1606 to overexpress it in Escherichia coli transformants. Deletion of the 5'-noncoding region as well as expression of the alpha-glucosidase gene under the control of the icp promotor of the insecticidal crystal protein gene from Bacillus thuringiensis subsp. sotto enhanced the enzyme productivity to 23.5 U/ml, which was 12,000-fold higher than that obtained by the strain SAM1606. The open reading frame corresponding to the alpha-glucosidase encoded 587 amino acid residues including a residue coded by the initiation codon TTG, and the molecular mass of the alpha-glucosidase from N-terminal serine was calculated to be 68,886 Da. Sequence analysis revealed that the SAM1606 alpha-glucosidase belonged to the alpha-amylase family. The SAM1606 alpha-glucosidase showed extremely high sequence identity (62-65%) to the Bacillus cereus and Bacillus thermoglucosidasius oligo-1,6-glucosidases, which were 72% identical to each other. Sequence identity in the suggested active site regions were essentially the same (80-82%) among these three enzymes. However, the substrate specificity of the SAM1606 alpha-glucosidase was significantly different from those of the oligo-1,6-glucosidases. The thermostability of these three alpha-glucosidases could be correlated with the increase in the number of proline residues, whose occurrence was predicted at beta turns and coils in the enzymes.
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PMID:Structure and expression of a gene coding for thermostable alpha-glucosidase with a broad substrate specificity from Bacillus sp. SAM1606. 812 87

The effect of eight anthelmintics (Rintal, Fenbesan, Telmin, Banminth, Pyrantel, Nilverm, Levamisol and Bioscardina) on the alpha- and gamma-amylases, trypsin, and lipase from pig's pancreas and gut of Ascaris suum was determined. In extracts from A. suum gut also the maltase, trehalase and saccharose activities were examined. All drugs tested did not influence on the host's alpha-amylase. Telmin and Bioscardina were inhibitors of gamma-amylase, Rintal and Telmin--of trypsin, Fenbesan and Bioscardina--of lipase from pig's pancreas. Among the parasite's enzymes the lipase was the most sensitive. Its activity was decreased (35-60%) by Telmin, Nilverm and both pyrantel derivatives. The activity of maltase and trehalase was reduced by Levamisole and Banminth, that of saccharose by Levamisole. It is concluded that the anthelmintics Levamisole and Banminth seemed the most efficient among the tested drugs because they did not alter the activity of host's enzymes and, showed the inhibitory effect on three of parasite's enzymes.
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PMID:[In vitro study of anthelmintic influence on activities of digestive enzymes in extracts from the gut of Ascaris suum and pig's pancreas]. 812 27


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