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)

High-pressure liquid chromatography and microcalorimetry have been used to study the thermodynamics of the hydrolysis reactions of a series of disaccharides. The enzymes used to bring about the hydrolyses were: beta-galactosidase for lactulose and 3-o-beta-D-galactopyranosyl-D-arabinose; beta-glucosidase for alpha-D-melibiose; beta-amylase for D-trehalose; isomaltase for palatinose; and alpha-glucosidase for D-turanose. The buffer used was sodium acetate (0.02-0.10 M and pH 4.44-5.65). For the following processes at 298.15 K: lactulose(aq) + H2O(liq) = D-galactose(aq) + D-fructose(aq), K0 = 128 +/- 10 and delta H0 = 2.21 +/- 0.10 kJ mol-1; alpha-D-melibiose(aq) + H2O(liq) = D-galactose(aq) + D-glucose(aq), K0 = 123 +/- 42 and delta H0 = -0.88 +/- 0.50 kJ mol-1; palatinose(aq) + H2O(liq) = D-glucose(aq) + D-fructose(aq), delta H0 = -4.44 +/- 1.1 kJ mol-1; D-trehalose(aq) + H2O(liq) = 2 D-glucose(aq), K0 = 119 +/- 10 and delta H0 = 4.73 +/- 0.41 kJ mol-1; D-turanose(aq) + H2O(liq) = D-glucose(aq) + D-fructose(aq), delta H0 = -2.68 +/- 0.75 kJ mol-1; and 3-o-beta-D-galactopyranosyl-D-arabinose(aq) + H2O(liq) = D-galactose(aq) + D- arabinose(aq),0H0 = 107 +/- 10 and delta H0 = 2.97 +/- 0.10 kJ mol-1.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Thermodynamics of hydrolysis of disaccharides. Lactulose, alpha-D-melibiose, palatinose, D-trehalose, D-turanose and 3-o-beta-D-galactopyranosyl-D-arabinose. 187 72

The hydroxylsine-linked disaccharide unit, 2-O-alpha-D-glucopyranosyl-O-beta-D-galactopyranosyl-hydroxylysine (Glc-Gal-Hyl), prepared from collagens, was hydrolyzed by a glucohydrolase present in rat spleens and lungs. This disaccharide unit was scarcely hydrolyzed by homogenates of intestines, livers, and kidneys, which had a high alpha-D-glucosidase activity for neutral glucosides. The Glc-Gal-Hyl glucohydrolase was purified from rat spleens by affinity chromatography and gel filtration to the extent that sodium dodecyl sulfate/polyacrylamide gel electrophoresis gave a single band stained by Coomassie blue G-250. This purified glucohydrolase had a pH optimum around 5.8, and the Michaelis constant was 5.9 mM when Glc-Gal-Hyl was used as a substrate. This enzyme did not hydrolyze neutral glucosides. It is concluded that this Glc-Gal-Hyl glucohydrolase is responsible for catabolism of the hydroxylsine-linked disaccharide unit derived from collagens in mammals.
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PMID:Enzymatic hydrolysis of disaccharide unit of collagen. Isolation of 2-O-alpha-D-glucopyranosyl-O-beta-D-galactopyranosyl-hydroxylysine glucohydrolase from rat spleens. 746 Sep 18

2,6-Dideoxy-7-O-(beta-D-glucopyranosyl) 2,6-imino-D-glycero-L-gulo- heptitol (7-O-beta-D-glucopyranosyl-alpha-homonojirimycin, 1) was isolated from the 50% methanol extract of the whole plant of Lobelia sessilifolia (Campanulaceae), which was found to potently inhibit rice alpha-glucosidase. Adenophorae radix, roots of Adenophora spp. (Campanulaceae), yielded new homonojirimycin derivatives, adenophorine (2), 1-deoxyadenophorine (3), 5-deoxyadenophorine (4), 1-C-(5-amino-5-deoxy-beta-D-galactopyranosyl)butane (beta-1-C-butyl-deoxygalactonojirimycin, 5), and the 1-O-beta-D-glucosides of 2 (6) and 4 (7), in addition to the recently discovered alpha-1-C-ethylfagomine (8) and the known 1-deoxymannojirimycin (9) and 2R,5R-bis(hydroxymethyl)-3R,4R- dihydroxypyrrolidine (DMDP, 10). Compound 4 is a potent inhibitor of coffee bean alpha-galactosidase (IC50 = 6.4 microM) and a reasonably good inhibitor of bovine liver beta-galactosidase (IC50 = 34 microM). Compound 5 is a very specific and potent inhibitor of coffee bean alpha-galactosidase (IC50 = 0.71 microM). The glucosides 1 and 7 were potent inhibitors of various alpha-glucosidases, with IC50 values ranging from 1 to 0.1 microM. Furthermore, 1 potently inhibited porcine kidney trehalase (IC50 = 0.013 microM) but failed to inhibit alpha-galactosidase, whereas 7 was a potent inhibitor of alpha-galactosidase (IC50 = 1.7 microM) without trehalase inhibitory activity.
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PMID:Homonojirimycin analogues and their glucosides from Lobelia sessilifolia and Adenophora spp. (Campanulaceae). 1078 88

New polyhydroxylated alkaloids, (2R,3R,4R)-2-hydroxymethyl-3,4-dihydroxypyrrolidine-N-propionamide from the root bark of Morus alba L., and 4-O-alpha-D-galactopyranosyl-calystegine B(2) and 3 beta,6 beta-dihydroxynortropane from the fruits, were isolated by column chromatography using a variety of ion-exchange resins. Fifteen other polyhydroxylated alkaloids were also isolated. 1-Deoxynojirimycin, a potent alpha-glucosidase inhibitor, was concentrated 2.7-fold by silkworms feeding on mulberry leaves. Some alkaloids contained in mulberry leaves were potent inhibitors of mammalian digestive glycosidases but not inhibitors of silkworm midgut glycosidases, suggesting that the silkworm has enzymes specially adapted to enable it to feed on mulberry leaves. The possibility of preventing the onset of diabetes and obesity using natural dietary supplements containing 1-deoxynojirimycin and other alpha-glucosidase inhibitors in high concentration is of great potential interest.
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PMID:Polyhydroxylated alkaloids isolated from mulberry trees (Morusalba L.) and silkworms (Bombyx mori L.). 1155 12