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)

Bacillus subtilis P-11, capable of producing extracellular maltase, was isolated from soil. Maximum enzyme production was obtained on a medium containing 2.0% methyl-alpha-D-glucose, 0.5% phytone, and 0.2% yeast extract. After the removal of cells, extracellular maltase was precipitated by ammonium sulfate (85% saturation). The enzyme was purified by using the following procedures: Sephadex G-200 column chromatography, diethylaminoethyl-Sephadex A-50 ion-exchange column chromatography, and a second Sephadex G-200 column chromatography. A highly purified maltase without amylase or proteinase activities was obtained. Some properties of the extracellular maltase were determined: optimum pH, 6.0; optimum temperature, 45 C, when the incubation time was 30 min; pH stability, within 5.5 to 6.5; heat stability, stable up to 45 C; isoelectric point, pH 6.0 (by gel-isoelectric focusing); molecular weight, 33,000 (by gel filtration with Sephadex G-200); substrate specificity: the relative rates of hydrolysis of maltose, maltotriose, isomaltose, and maltotetraose were 100:15:14:4, respectively, and there was no activity toward alkyl or aryl-alpha-D-glucosides, amylose, or other higher polymers. Transglucosylase activity was present. Glucose and tris(hydroxymethyl)aminomethane were competitive inhibitors with Ki values of 4.54 and 75.08 mM, respectively; cysteine was a noncompetitive inhibitor. Michaelis constants were 5 mM for maltose, 1 mM for maltoriose, and 10 mM for isomaltose. A plot of pKm (-log Km) versus pH revealed two deflection points, one each at 5.5 and 6.5; these probably corresponded to an imidazole group of a histidine residue in or near the active center; this assumption was supported by the strong inhibition of enzyme activity by rose bengal.
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PMID:Purification and some properties of an extracellular maltase from Bacillus subtilis. 0 2

Mycelial and yeast forms of P. brasiliensis were tested for several glucohydrolases. In addition to high levels of beta-glucanases, low amounts of alpha-glucanase, chitinase and maltase were found. Tests for invertase, amylase and lactase were negative. The levels of beta-1,3-glucanase were higher in the mycelial form. The shift to the mycelial phase correlated with an increase in the levels of beta-1,3-glucanase. The enzyme was present in the cytoplasm, cell wall and culture medium. The extracellular enzyme was purified 42 fold by ammonium sulphate precipitation and gel filtration. Maximal activity was obtained at 60 degrees C and pH of 5.0 (acetate buffer or pH 6.0 (phosphate buffer). Its Km was 0.205 mg/ml. The cell wall-bound enzyme showed a higher temperature optimum. Optimum pH and Km were also slightly different. Following treatment of the cell walls with chitinase, beta-1,3-glucanase was released into the medium.
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PMID:Beta-1-3-glucanase and dimorphism in Paracoccidioides brasiliensis. 4 May 30

Because the pancreas undergoes involutional changes during total parenteral nutrition (TPN) and because pancreatico-biliary secretions are trophic to the intestine, we studied jejunal and ileal structure and function and exocrine pancreatic function before and after 6 weeks of TPN in two groups of beagle dogs, one of which had TPN alone, the other having TPN plus daily stimulation of pancreatico-biliary secretions with intravenous infusions of cholecystokinin (CCK) and secretin. The injections of 1 U each per kg of body weight per day of CCK and secretin completely prevented the proximal and distal small bowel mucosal hypoplasia which developed in the TPN alone group. They also resulted in significant increases in in vivo galactose absorption (64 mM) per unit length of jejunum and ileum. However, there was no significant change in mucosal alpha-glucosidase and catalase activity or in in vitro mucosal uptake of 1 mM [14C]leucine when expressed per unit weight of intestinal mucosa. The capacity of the pancreas to respond to CCK and secretin was unaffected by excluding food from the intestine with 6 weeks of TPN in terms of pH, volume, and peak secretion rates of bicarbonate and protein, but maximum amylase output (units per 15 min per kg of body weight) fell significantly (P less than 0.05) from a mean of 1022 +/- 155 to 874 +/- 426 in TPN alone group and to 472 +/- 79 in the TPN dogs given CCK and secretin. These results show that daily CCK and secretin is trophic to the intestine of dogs nourished by TPN but do not indicate whether this trophic effect is attributable to CCK alone, secretin alone, the combination of the two hormones, or to the resultant stimulation of pancreatico-biliary secretions.
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PMID:Cholecystokinin and secretin prevent the intestinal mucosal hypoplasia of total parenteral nutrition in the dog. 12 2

I describe a new kinetic enzymatic saccharogenic method for assaying alpha-amylase in human serum and urine. alpha-Amylase liberates maltose from starch. This is successively acted on by alpha-glucosidase, mutarotase, and glucose dehydrogenase. The resulting conversion of NAD+ to NADH, measured at 340 nm, during a 20-min incubation reflects amylase activity. Endogenous glucose is destroyed before measurement of amylase activity is begun.
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PMID:New saccharogenic determination of alpha-amylase in serum and urine. 21 41

alpha-Amylase can be measured continuously with the aid of 4-nitrophenyl glucosides, especially 4-nitrophenyl maltotrioside; the large scale enzymatic synthesis of this compound seems to be possible. Another method, which does not suffer from interference by endogenous glucose, consists of the hydrolysis of maltotetraose by alpha-amylase, followed by the determination of maltose. The substrate and the auxiliary enzymes are, however, relatively expensive. Continous methods, based on the measurement of the glucose released by alpha-amylase, are more sensitive. However, they suffer from interference by blood sugar, with exception of mechanized procedures, which remove glucose by gel filtration of the sample. Moreover these methods need alpha-glucosidase, which degrades maltooligosaccharides consisting of less than seven glucose units, whereas higher polymerized substrates show slower degradation rates by amylase, and the kinetics are not easy to understand.
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PMID:alpha-Amylase assay: current state and future development. 31 93

During meiosis in Saccharomyces cerevisiae, the polysaccharide glycogen is first synthesized and then degraded during the period of spore maturation. We have detected, in sporulating yeast strains, an enzyme activity which is responsible for the glycogen catabolism. The activity was absent in vegetative cells, appeared coincidently with the beginning of glycogenolysis and the appearance of mature ascospores, and increased progressively until spourlation was complete. The specific activity of glycogenolytic enzymes in the intact ascus was about threefold higher than in isolated spores. The glycogenolysis was not due to combinations of phosphorylase plus phosphatase or amylase plus maltase. Nonsporulating cells exhibited litle or no glycogen catabolism and contained only traces of glycogenolytic enzyme, suggesting that the activity is sporulation specific. The partially purified enzyme preparation degraded amylose and glycogen, releasing glucose as the only low-molecular-weight product. Maltotriose was rapidly hydrolyzed; maltose was less susceptible. Alpha-methyl-D-glucoside, isomaltose, and linear alpha-1,6-linked dextran were not attacked. However, the enzyme hydrolyzed alpha-1,6-glucosyl-Schardinger dextrin and increased the beta-amylolysis of beta-amylase-limit dextrin. Thus, the preparation contains alpha-1,4- and alpha-1,6-glucosidase activities. Sephadex G-150 chromatography partially resolved the enzyme into two activities, one of which may be a glucamylase and the other a debranching enzyme.
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PMID:Glycogenolytic enzymes in sporulating yeast. 35 Aug 52

The distribution of lysozyme, alkaline phosphatase, aminopeptidase, maltase and amylase was studied throughout the small intestine of the adult rat. Lysozyme activity increases along the length of the small intestine and the behaviour of this enzyme slightly differs from the mucosal enzymes reported in this investigation. A positive correlation is found between the percentage of crypts with granulated Paneth cells and the lysozyme activity. This corroborates with the secretory origin of this enzyme from these intestinal cells.
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PMID:The quantitative distribution of certain enzymes along the small intestine of the rat and its correlation with the villous area and the Paneth cells. 35 72

In rats fed for 4, 15, and 30 days with increased amount of proteins, lipids, and carbohydrates, considerable shifts occurred in activity of enzymes of the pancreas (amylase, protease, and lipase) and small intestine (gamma--amylase, maltase group, invertase, peptidhydrolase, monoglyceriflipase). Mathematical analysis suggested a close connection between the adaptive shifts in the enzyme systems maintaining the lumen and the membrane types of digestion. The protein diet augments the proteolytic enzyme chain the lipid diet--the lipolytic chain, and the carbohydrate diet--the carbohydrate chain. The shifts should be regarded as an integrative adaptive response of the enzyme spectrum of the pancreas and small intestine to alterations in the food composition.
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PMID:[Interrelationships between the enzymatic functions of the pancreas and small intestine during adaptive processes]. 36 44

Modifications of some enzyme activities in parotid tissue homogenates have been studied in animals which were also examined for morphological changes and for plasma and parotid amylase activity. Results from irradiated animals show a certain increase in maltase activity. Alkaline phosphatase and LAP show no significant variations; a similar behaviour is shown by lysosomal enzymes and protein content. A different pattern was seen by comparing the curves of these enzymes with those of the same activity in the small intestine. This result appears to be due to the different radiosensitivity of these tissues.
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PMID:Radiation effects on the parotid gland of mammals. Part 3: Behaviour of enzyme activity after irradiation. 38 45

The effect of exposure of Channa punctatus to a sub-lethal concentration of lead nitrate on the activities of alkaline phosphatase, acid phosphatase amylase, maltase, lactase, trypsin and pepsin has been investigated. A decrease in the activity of alkaline phosphatase has been recorded after 15 days of exposure but there was no significant change after 30 days. Acid phosphatase showed an elevation in activity of both stages. All the three carbohydrases shows elevation after 15 days, followed by an inhibition after 30 days of treatment. The activity of pepsin and trypsin remained above the normal level throughout the tensure of the experiment reveal that the pattern of alteration in enzyme activities is different in liver and digestive system.
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PMID:Alternations in the activity of some digestive enzymes of Channa punctatus, exposed to lead nitrate. 66 84


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