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)

Various enzyme activities involved in the active transport system, glycolysis, and digestion were assayed in various parts of the gastrointestinal tracts of germfree, conventional, and gnotobiotic rats associated with indigenous bacteria. The activity levels of alkaline phosphatase, glucose 6-phosphatase, adenosine triphosphatase, and disaccharidases in the upper small intestine were highest in all parts of the gastrointestinal tracts of various kinds of gnotobiotic, conventional, and germfree rats. Alkaline phosphatase, glucose 6-phosphatase, and adenosine triphosphatase activities in the upper small intestine of germfree rats were, respectively, 2.3-, 2.9-, and 1.7-fold higher than those in conventional rats. Similar to the results of these enzymes, sucrase, maltase, trehalase, and lactase activities in the upper small intestine of germfree rats were, respectively, 1.6-, 1.5-, 2.3-, and 1.8-fold higher than those in conventional rats. In various gnotobiotic rats, enzyme activity levels were intermediate between those in germfree and conventional rats. These findings suggest that those enzymatic activities are strongly depressed by the association with the indigenous microorganisms in the epithelial mucosa of the upper small intestine of rats. The levels of pyruvate kinase, hexokinase, and lactate dehydrogenase activities were highest, respectively, in the stomach, cecum, and the upper small intestine and cecum in all parts of the gastrointestinal tracts in various kinds of gnotobiotic, conventional, and germfree rats. It was also shown that six kinds of gastrointestinal bacteria, including lactobacilli, significantly depressed the enzyme activity levels to levels between those of the germfree and conventional rats in the upper small intestine of gnotobiotic rats.
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PMID:Intestinal enzyme activities in germfree, conventional, and gnotobiotic rats associated with indigenous microorganisms. 20 6

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

The activities of rat intestinal enzymes, sucrase, lactase, maltase, trehalase, gamma-glutamyltransferase, leucylnaphthylamide-hydrolyzing activity, and the transport system for glucose follow diurnal rhythms on ad libitum and restricted feeding regimes. In response to 6 days of restricted feeding, food available between 1400 and 1800 Eastern Standard Time, all rhythms shifted in time and the daily levels of activities were changed. Alkaline phosphatase activity followed a diurnal rhythm only in restricted fed animals. In restricted fed rats several activity patterns were observed, some with short periods of maximum activity, 3 h or less, and some with plateaus of maximum activity, 5-9 h long. In respect to the time of day of the synchronizer, sucrase peaked before feeding, glucose transport peaked during feeding, alkaline phosphatase peaked after feeding, and the other enzymes had higher levels of activity before, during and after feeding. The effect of restricted feeding on the daily activity levels were: a decrease in leucylnaphthylamide-hydrolyzing activity, no change in alkaline phosphatase, and increases in the others. These enzyme and transport systems exhibit a large amount of individual regulation or control as reflected by the lack of a uniform activity pattern and response to the synchronizer, and the variation in direction and magnitude of the adaptations to restricted feeding.
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PMID:Effect of changes in feeding schedule on the diurnal rhythms and daily activity levels of intestinal brush border enzymes and transport systems. 24 Apr 40

Pseudomonas fluorescens W uses maltose exclusively by hydrolyzing it to glucose via an inducible alpha-glucosidase (alpha-D-glucoside glucohydrolase, EC 3.2.1.20). No evidence for phosphorolytic cleavage or oxidation to maltobionic acid was found in this organism. The alpha-glucosidase was totally intracellular and was most active at pH of 7.0. Induction occurred when cells were incubated with maltotriose or maltose. Induction was rapid and easily detectable within the first 5 min after the addition of the inducer. Glucose and its derivatives did not repress induction. Cells growing on DL-alanine or succinate plus maltose exhibited lower levels of alpha-glucosidase than those grown on maltose alone or maltose plus glucose. Induction required both messenger ribonucleic acid and protein synthesis.
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PMID:Maltose metabolism of Pseudomonas fluorescens. 24 Aug 5

The glucosyltransferase (UDP-glucose galactosylhydroxylsine collagen glucosyltransferase, EC 2.4.1.?.) was purified 50-fold from calf arterial tissue by ammonium sulfate precipitation, gel filtration and electrofocusing. The purified enzyme has a molecular weight of 72 000 and a requirement for Mn2. It resolves into two activity peaks when submitted to electrofocusing (isoelectric point at pH 4.2 and 8.1) or disc electrophoresis and exhibits a double pH optimum (pH 8.3 and 9.9). The enzyme was found to transfer glucose from UDP-glucose to the denatured forms of citrate-soluble calf skin collagen (I), the alphal chain (II) and the beta12 component (III) derived from it, and of an acetic-acid-souble collagen preparation (IV) obtained from alkali-treated calf arterial tissue. The Km values for the substrates were 1.67 X 10(-4) (I), 6.3 X 10(-4) (II), 3.3 X 10(-4) (III) and 2.8 X 10(-4) mol/l (IV), indicating that the enzyme has the greatest affinity for the calf skin collagen. The glucose transferred to hydroxylysine-linked galactose residues may be released subsequently by the action of a specific alpha-glucosidase purified from bovine spleen. The results support the assumtion that the glucosylation step in the course of the (pro-)-collagen biosynthesis depends on special structural features of the substrate and may be controlled by a specific alpha-glucosidase.
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PMID:Purification and properties of UDP-glucose galactosylhydroxylysine collagen glucosyltransferase (EC 2.4.1.?) from bovine arterial tissue. 24 97

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

Mutants altered in carbon catabolite regulation have been isolated by selecting for mutants of the areA217 strain capable of using acetamide as the sole nitrogen source in the presence of sucrose. In addition to creA mutants described previously be Arst and Cove, strains with mutations in two new genes, creB and cre C, have been found. The creB and creC mutants grow poorly on some sole carbon sources and have low levels of some enzymes of carbon catabolism e.g. beta-galactosidase and D-quinate dehydrogenase. The creB and creC mutants are hypersensitive to fluoroacetate, fluoroacetamide and allyl alcohol in the presence of glucose or sucrose but not glycerol; and the enzymes, acetamidase and alcohol dehydrogenase, are less sensitive to carbon catabolite repression than the wild-type strain. Extracellular protease and alpha-glucosidase enzyme activities are elevated in creB and creC mutants, while L-proline and L-glutamate uptake capacities are lower in both the presence and absence of glucose. Interactions between creA, B and C mutations have been investigated in double mutants, and the dominance properties of creB and creC mutants determined. The results indicate that the creB and creC genes may have a regulatory role in the control of carbon catabolism.
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PMID:Pleiotropic mutants of Aspergillus nidulans altered in carbon metabolism. 32 Apr 55

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

Extracts of Streptococcus mitis ATCC 903 were analysed for beta-fructofuranosidase and alpha-glucosidase activities by isoelectric focusing in thin-layer polyacrylamide gels combined with zymogram procedures. Three bands of activity were visualized in the gels after incubation with sucrose (pI 4.05, 4.25 and 4.85) and three other bands after incubation with p-nitrophenyl alpha-D-glucopyranoside (pI 3.90, 4.45 and 4.65). The enzymes responsible for the reaction with sucrose were identified as beta-fructofuranosidases (EC 3.2.1.26) for the following reasons: identical enzyme bands were visualized in the gels after incubation with raffinose; no enzyme bands appeared in the gel after incubation with the alpha-glucosides maltose, turanose, trehalose and melezitose; and the soluble fraction hydrolysed sucrose to equimolar amounts of glucose and fructose.
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PMID:Isoelectric focusing studies on the beta-fructofuranosidases and alpha-glucosidases of Streptococcus mitis. 35 25

We evaluated the Harleco alpha-glucosidase/hexokinase/glucose-6-phosphate dehydrogenase-coupled alpha-amylase method, bu use of the GEMSAEC centrifugal analyzer. Performance evaluation included kinetic studies of substrate and maltose hydrolysis as well as effects of endogenous glucose and fructose. The reagent was found to give a linear response with alpha-amylase activity to greater than 1200 U/liter. Within-run precision resulted in coefficients of variation (CV) of 0.9 to 3.2% over the range studied. Day-to-day precision corresponded to CV's of 2.4 to 4.4% over the same range of alpha-amylase procedure was found to be good (r = 0.997) for patients' sera examined.
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PMID:Enzyme-coupled ultraviolet determination of alpha-amylase activity with the GEMSAEC centrifugal analyzer. 35 41


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