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 gal3 mutation of Saccharomyces, which is associated with an impairment in the utilization of galactose, has been shown to be pleiotropic, causing similar impairments in the utilization of melibiose and maltose. Milibiose utilization and alpha-galactosidase production are directly controlled by the galactose regulatory elements i, c, and GAL4. The fermentation of maltose and the induction of alpha-glucosidase are regulated independently of the i, c, GAL4 system. The production of alpha-galactosidase and galactose-1-phosphate uridyl transferase is coordinate in galactokinaseless strains. Galactose serves as a nonmetabolized, gratuitous inducer of alpha-galactosidase in strains lacking the genes for one or more of the Leloir pathway enzymes.
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PMID:Genetic co-regulation of galactose and melibiose utilization in Saccharomyces. 124 60

Ascorbic acid 2-O-alpha-glucoside (AA-2G) has been reported to have antiscorbutic activity in guinea pigs. The present experiments examined the metabolic fate of AA-2G following ingestion. Oral administration of AA-2G (96 mg) to guinea pigs resulted in a remarkable increase of ascorbic acid in various tissues as well as plasma, but intact AA-2G was detected only in plasma, but intact AA-2G was detected only in plasma and urine in small amounts. The absorption efficiency of AA-2G and ascorbic acid was further determined by using everted gut sacs of rats. Ascorbic acid released from AA-2G on the mucosal side was effectively taken up across intestinal membranes into the serosal side, whereas AA-2G poorly permeated via a passive transport system. The hydrolysis of AA-2G on the mucosal surface of everted gut was completely inhibited by an alpha-glucosidase inhibitor and the hydrolytic activity of a crude membrane extract diminished to one-forth after immunoprecipitation with the antibody specific to maltase. From these results, it is concluded that ingested AA-2G serves as a vitamin C source through the hydrolysis by intestinal membrane-bound alpha-glucosidase, mainly maltase, and the subsequent absorption of released ascorbic acid.
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PMID:Evaluation of ascorbic acid 2-O-alpha-glucoside as vitamin C source: mode of intestinal hydrolysis and absorption following oral administration. 129 35

In the human adenocarcinoma cell line Caco-2 a substantial amount of a precursor form of the lysosomal enzyme alpha-glucosidase is not segregated into lysosomes, but instead secreted from the apical membrane. In this study we addressed the question whether this process is mediated by mannose 6-phosphate receptors. The subcellular distribution of the cation-independent mannose 6-phosphate receptor was studied by means of electron microscopic immunocytochemistry. The bulk of label was found in the perinuclear region in electron-lucent and dense vesicles, some of the latter bearing a coat. Receptor-containing dense vesicles were also found throughout the cytoplasm. In the apical part of the cells, label for the receptor was present over the surrounding membrane and the interior vesicles of multivesicular bodies, but not over lysosomes. Label on the plasma membrane was mainly restricted to the apical domain. In contrast to alpha-glucosidase, the secreted forms of the lysosomal enzymes cathepsin D, beta-hexosaminidase and beta-glucuronidase are mainly found in the basolateral medium. Enzyme activity measurements and immunoprecipitation of metabolically labeled cells showed that incubation with NH4Cl leads to an enhanced secretion of these enzymes into the basolateral medium, but has no effect on the basolateral secretion of alpha-glucosidase. In addition, NH4Cl caused a minor decrease in the secretion of these enzymes from the apical side and had little or no effect on the secretion of alpha-glucosidase.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The cation-independent mannose 6-phosphate receptor is not involved in the polarized secretion of lysosomal alpha-glucosidase from Caco-2 cells. 132 37

We investigated enzymes participating in alpha-glucoside formation, a novel metabolic pathway of xenobiotics in a metabolic study of indeloxazine hydrochloride in rats. When rat tissue homogenates and the indeloxazine metabolite trans-4-(2-morpholinylmethoxy)-1,2-indandiol (M-2) were incubated, M-2-alpha-glucoside formation was observed in liver. This reaction was almost completely inhibited by the alpha-glucosidase inhibitor acarbose. The liver homogenate was then separated into subcellular fractions and an acid alpha-glucosidase in lysosomes and two neutral alpha-glucosidases in microsomes and cytosol were partially purified. The chromatographic behavior and optimum pH of the glucosyltransferase activity of each of the enzyme preparations were almost identical with those of alpha-glucosidase (hydrolase) activity of the same specimen, suggesting the former activity to be also due to alpha-glucosidase. Agreeing with their hydrolytic substrate specificities, the acid enzyme transferred glucose to M-2 from a series of glucose derivatives, ranging from low molecular maltosaccharides to high molecular glycogen, whereas the neutral enzymes took only low molecular maltosaccharides as glucosyl donors. These results led to the conclusion that the formation of alpha-glucoside conjugates is catalyzed by more than one alpha-glucosidase in the liver and uses maltosaccharides or glycogen as glucosyl donors. Several other diol structure-bearing compounds were found in vitro to give rise to alpha-glucoside conjugates, and the mechanism of alpha-glucoside formation is discussed.
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PMID:Alpha-glucoside formation of xenobiotics by rat liver alpha-glucosidases. 135 26

The gene coding for a thermostable exo-alpha-1,4-glucosidase (alpha-glucoside glucohydrolase: EC 3.2.1.20) of Bacillus stearothermophilus ATCC 12016 was cloned within a 2.8-kb AvaI fragment of DNA using the plasmid pUC19 as a vector and Escherichia coli JM109 as a host. E. coli with the hybrid plasmid accumulated exo-alpha-1,4-glucosidase mainly in the cytoplasm. The level of enzyme production was about sevenfold higher than that observed for B. stearothermophilus. The cloned enzyme coincided absolutely with the B. stearothermophilus enzyme in its relative molecular mass (62,000), isoelectric point (5.0), amino-terminal sequence of 15 residues (Met-Lys-Lys-Thr-Trp-Trp-Lys-Glu-Gly-Val-Ala-Tyr-Gln-Ile-Tyr-), the temperature dependency of its activity and stability, and its antigenic determinants.
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PMID:Cloning and expression of a thermostable exo-alpha-1,4-glucosidase gene from Bacillus stearothermophilus ATCC12016 in Escherichia coli. 136 46

alpha- And beta-glucoside derivatives of validamine and valienamine were prepared by enzymatic transglucosidation using alpha- and beta-glucosidase of Rhodotorula lactosa. The structures of these derivatives have been elucidated by 13C- and 1H-nuclear magnetic resonance spectral analysis. Thus, 7-alpha-glucoside, 7-alpha-isomaltoside, and 4-alpha-glucoside of validamine and 7-alpha-glucoside, 7-alpha-isomaltoside, 4-alpha-glucoside, and 4-alpha-isomaltoside of valienamine were obtained from maltose and validamine or valienamine using alpha-glucosidase. 7-beta-glucoside, 2-beta-glucoside, and 4-beta-glucoside of validamine or valienamine were obtained from cellobiose and validamine or valienamine using beta-glucosidase. These derivatives were tested for alpha-glucosidase inhibitory activity on rat small intestinal glycosidases.
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PMID:Enzymatic synthesis of glucoside derivatives of validamine and valienamine. 139 6

A highly thermostable alpha-glucosidase (E C.3.2.1.20) from an extreme thermophile, Thermus thermophilus HB 8, was purified to homogeneous by ammonium sulfate fractionation, DEAE-cellulose chromatography and preparative slab gel electrophoresis. The enzyme was purified 17 fold with 21% recovery of activity. The enzyme had a molecular weight of 67000 by SDS-PAGE. The isoelectric point was pH4.5 by IEF on PAG. The enzyme hydrolized p-nitrophenyl-alpha-glucoside (PN-PG), sucrose and maltose, but not cellobiose, melibiose and soluble starch. The km value for PNPG was 0.4mmol/L, the Vmax was 0.29 mumol.min-1.mg-1. The enzyme exhibited high thermostability. After incubation at 90 degrees C for 10 h in 50 mmol/L acetate buffer pH 5.8, the enzyme retained 90% of its original activity. The half-live (t1/2) at 95 degrees C was 108 min. The enzyme was activated by Mg2+, Mn2+, Ca2+, Ba2+ and strongly inhibited by Hg2+, Cu2+. Modification of the enzyme by EDC or DEPC led to complete loss of activity, which suggests that carboxyl group(s) and histidine residue(s) are essential for activity of alpha-glucosidase.
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PMID:[Purification and characterization of alpha-glucosidase from an extreme thermophile, Thermus thermophilus HB 8]. 141 35

Metronidazole (Flagyl), an antibiotic commonly used in treating intestinal infections, when administered orally at a dose level of 100 mg/kg body weight daily for 7 days to rats brought about a significant elevation of the uptake of end-product nutrients like D-glucose, L-alanine, L-aspartic acid and L-leucine in the intestinal segments. Brush border membrane-bound hydrolytic enzymes, i.e. sucrase, lactase, maltase, alkaline phosphatase and leucine aminopeptidase levels, were also elevated. Substrate kinetic analysis of the uptake of nutrients as well as the enzymes indicated that the drug increased the maximum of apparent initial velocity, while the substrate affinity constants did not change. Studies of the temperature-dependent parameters of the nutrient uptake and the enzyme activity revealed that metronidazole did not induce any shift in the transition temperature (T(o)) for the uptake but the energy of activation (Ea) was reduced in all the cases except those of maltase and leucine aminopeptidase, which registered an increase in Ea and a marginal shift in T(o), respectively. A significant elevation was seen in the levels of membrane cholesterol, phospholipid, ganglioside and plasmalogen in metronidazole-treated animals, while triglycerides and the non-esterified fatty acids remained unaffected. The effects produced by metronidazole treatment persisted in the animals, which were allowed a recovery period of 7 days after the drug regimen.
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PMID:Effect of the antiprotozoal agent metronidazole (Flagyl) on absorptive and digestive functions of the rat intestine. 147 60

Two methyl acarviosin analogues 3a and 4a, having the alpha-manno configuration, and their dihydro derivatives 6a and 7a were synthesised by coupling the protected pseudo-sugar epoxides with methyl 4-amino-4-deoxy- and -4,6-dideoxy-alpha-D-mannopyranoside. Similarly, two analogous compounds 5a and 8a composed of the 1,6-anhydro-beta-D-mannopyranose residues were prepared. Compound 7a showed mild inhibitory activity against Jack bean alpha-D-mannosidase, and 3a was a moderate inhibitor of both alpha-D-mannosidase and yeast alpha-D-glucosidase.
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PMID:Synthesis and enzyme-inhibitory activity of methyl acarviosin analogues having the alpha-manno configuration. 149 24

Nine analogues of methyl acarviosin (1), the core structure of acarbose and its homologues, the 6-hydroxy-(2), 6-azido-(3), 6-amino- (4), 6-acetamido-(5), 6-methoxy-(6), 6-hydroxy-2-O-methyl-(8), and 6-hydroxy-3-O-methyl derivatives (9), including the 5-methoxycarbonyl analogue (7) and 3,6-anhydro derivative (10) of 2, were synthesized by chemical modification of the sugar part of 2 derived by condensation of methyl 3,4-anhydro-alpha-D-galactopyranoside (17) and 4,7:5,6-di-O-isopropylidenevalienamine (26) or by direct coupling between 26 and the 6-substituted methyl 3,4-anhydro-alpha-D-galactopyranoside derivatives. Compounds 2 and 8 show notable inhibitory activity against yeast alpha-D-glucosidase almost comparable to that of 1. Introduction of a polar substituent at C-6 of 1 decreases the inhibitory activity. Interestingly, inversion of the conformation of the sugar part of 1 by introduction of the 3,6-anhydro bridge elicits almost no effect on the inhibitory activity.
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PMID:Chemical modification of the sugar part of methyl acarviosin: synthesis and inhibitory activities of nine analogues. 152 83


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