Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

A most potent alpha-glucosidase inhibitor named salacinol has been isolated from an antidiabetic Ayurvedic traditional medicine, Salacia reticulata WIGHT, through bioassay-guided separation. The absolute stereostructure of salacinol was determined on the basis of chemical and physicochemical evidence, which included the alkaline degradation of salacinol to 1-deoxy-4-thio-D-arabinofuranose and the X-ray crystallographic analysis, to be the unique spiro-like configuration of the inner salt comprised of 1-deoxy-4-thio-D-arabinofuranosyl sulfonium cation and 1'-deoxy-D-erythrosyl-3'-sulfate anion. Salacinol showed potent inhibitory activities on several alpha-glucosidases, such as maltase, sucrase, and isomaltase, and the inhibitory effects on serum glucose levels in maltose- and sucrose-loaded rats (in vivo) were found to be more potent than that of acarbose, a commercial alpha-glucosidase inhibitor.
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PMID:Absolute stereostructure of potent alpha-glucosidase inhibitor, Salacinol, with unique thiosugar sulfonium sulfate inner salt structure from Salacia reticulata. 1188 16

Beta-amylase (EC 3.2.1.2) was isolated from germinating millet (Panicum miliaceum L.) seeds by a procedure that included ammonium sulfate fractionation, chromatography on DEAE-cellulofine and CM-cellulofine, and preparative isoelectric focusing. The enzyme was homogeneous by SDS-PAGE. The M(r) of the enzyme was estimated to be 58,000 based on its mobility on SDS-PAGE and gel filtration with TSKgel G4000SW(XL), which showed that it is composed of a single unit. The isoelectric point of the enzyme was 4.62. The enzyme hydrolyzed malto-oligosaccharides more readily as their degree of polymerization increased, this being strongest for malto-oligosaccharides larger than 13 glucose residues and very weakly for maltotriose. Amylose, amylopectin and soluble starch were the most suitable substrates for the enzyme. While the enzyme showed some activity against native starch by itself, starch digestion was accelerated 2.5-fold using alpha-amylase, pullulanase and alpha-glucosidase. This enzyme appears to be very important for the germination of millet seeds.
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PMID:Beta-amylase in germinating millet seeds. 1456 8

The expression of alpha-1,4-glucosidase activity was fluorometrically and electrophoretically assessed in the epididymal fluid and seminal plasma of stallions. alpha-Glucosidase specific activity in the epididymis increased significantly from the proximal caput to the cauda. Stallion epididymal glucosidase maintained activity in a wide range of pH, with two distinct peaks (around pH 4.0 and 6.0, respectively). Enzyme activities at different pH, inhibition assays with sodium dodecyl sulfate (SDS) and maltotriose (MTT, selective inhibitors of alpha-glucosidases "acidic" and "neutral" isoforms, described in other tissues) and the electrophoretic analysis in native and native/SDS-PAGE conditions, indicated that stallion epididymal glucosidase was due to two catalytically active forms. These forms, analyzed by non-denaturing electrophoresis, exhibited different electrophoretic mobility and molecular weight. Samples from the proximal caput of the epididymis were rich in Form II or "neutral" form, whereas the "acid" or Form I seemed to be predominate in the cauda epididymal region. At physiological pH, Form II was predominant in the seminal plasma. The physiological role(s) of these forms is uncertain, but based on their ability to hydrolyze glucosidic linkage, they probably are involved in degradation/modifications of epididymal fluid and/or spermatozoa glycoconjugates, thereby participating in plasma membrane remodeling associated with sperm maturation.
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PMID:Identification and partial characterization of alpha-1,4-glucosidase activity in equine epididymal fluid. 1503 84

The syntheses of two ammonium salts of 1,4-dideoxy-1,4-imino-d-galactitol containing erythritol sulfate side chains are described. The parent compound is a known inhibitor of the enzyme UDP-galactopyranose mutase (UDP-galactopyranose furanomutase, E.C. 5.4.99.9), which is responsible for the conversion of UDP-galactopyranose into UDP-galactofuranose and is presumably protonated in its active form. The side chain was chosen because it is present in a known sulfonium ion alpha-glucosidase inhibitor, salacinol. The syntheses of the selenonium analogues derived from 1,4-dideoxy-1,4-seleno-d-galactitol are also described. The synthetic strategy in the syntheses of all four salts involved the nucleophilic attack of a protected derivative of the alditol at the least hindered carbon of 2,4-O-benzylidene d- or l-erythritol-1,3-cyclic sulfate to give adducts that were subsequently deprotected. The importance of different protecting groups used in the various syntheses is also highlighted. Enzyme inhibition assays carried out on these compounds, and the corresponding sulfonium ions synthesized previously, show that they are poor inhibitors of UDP-galactopyranose mutase.
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PMID:Synthesis of novel ammonium and selenonium ions and their evaluation as inhibitors of UDP-galactopyranose mutase. 1533 48

A method was developed to detect and identify Enterobacter sakazakii in environmental samples. The method is based on selective enrichment at 45+/-0.5 degrees C in lauryl sulfate tryptose broth supplemented with 0.5 M NaCl and 10 mg/liter vancomycin (mLST) for 22 to 24 h followed by streaking on tryptone soy agar with bile salts. When exposed to light during incubation at 37 degrees C, E. sakazakii produces yellow colonies within 24 h; identification was confirmed by testing for alpha-glucosidase activity and by using API 20E strips. All of the E. sakazakii strains tested (n = 99) were able to grow in mLST at 45+/-0.5 degrees C, whereas 35 of 39 strains of potential competitors, all belonging to the Enterobacteriaceae, were suppressed. A survey was carried out with 192 environmental samples from four different milk powder factories. Using this new protocol, E. sakazakii was isolated from almost 40% of the samples, whereas the reference procedure (enrichment in buffered peptone water, isolation on violet red bile glucose agar, and biochemical identification of randomly chosen colonies) only yielded 26% positive results. This selective method can be very useful for the rapid and reliable detection of E. sakazakii in environmental samples.
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PMID:A simple and rapid cultural method for detection of Enterobacter sakazakii in environmental samples. 1569 Aug 5

An alpha-glucosidase (alpha-D-glucoside glucohydrolase, EC 3.2.1.20) was isolated from germinating millet (Panicum miliaceum L.) seeds by a procedure that included ammonium sulfate fractionation, chromatography on CM-cellulofine/Fractogel EMD SO(3), Sephacryl S-200 HR and TSK gel Phenyl-5 PW, and preparative isoelectric focusing. The enzyme was homogenous by SDS-PAGE. The molecular weight of the enzyme was estimated to be 86,000 based on its mobility in SDS-PAGE and 80,000 based on gel filtration with TSKgel super SW 3000, which showed that it was composed of a single unit. The isoelectric point of the enzyme was 8.3. The enzyme readily hydrolyzed maltose, malto-oligosaccharides, and alpha-1,4-glucan, but hydrolyzed polysaccharides more rapidly than maltose. The K(m) value decreased with an increase in the molecular weight of the substrate. The value for maltoheptaose was about 4-fold lower than that for maltose. The enzyme preferably hydrolyzed amylopectin in starch, but also readily hydrolyzed nigerose, which has an alpha-1,3-glucosidic linkage and exists as an abnormal linkage in the structure of starch. In particular, the enzyme readily hydrolyzed millet starch from germinating seeds that had been degraded to some extent.
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PMID:Purification and characterization of an alpha-glucosidase from germinating millet seeds. 1584 3

The synthesis of analogues of the naturally occurring glycosidase inhibitor, salacinol, in which the D-arabinitol ring has been replaced by D-lyxitol or D-ribitol, is described. Salacinol is one of the active principles in the aqueous extracts of Salacia reticulata, which are traditionally used in India and Sri Lanka for the treatment of Type II diabetes. The synthetic strategy relies on the nucleophilic attack of 1,4-anhydro-2,3,5-tri-O-p-methoxybenzyl-4-thio-D-lyxitol or 1,4-anhydro-2,3,5-tri-O-p-methoxybenzyl-4-thio-D-ribitol at the least hindered carbon of the benzylidene-protected L-cyclic sulfate derived from L-erythritol. Screening of these compounds against recombinant human maltase glucoamylase (MGA), a critical intestinal glucosidase involved in the processing of oligosaccharides of glucose into glucose itself, shows that they are not effective inhibitors of MGA and demonstrates the importance of the d-arabinitol configuration in the heterocyclic ring for effective inhibition.
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PMID:Synthesis of D-lyxitol and D-ribitol analogues of the naturally occurring glycosidase inhibitor salacinol. 1619 22

Bacillus brevis NRRL B-4389 produced extracellular maltase (alpha-glucosidase; EC 3.2.1.20) only in the presence of short alpha-1,4-glucosidic polymers, such as maltose and maltotriose. An optimum medium was developed; it contained 2.5% maltose, 0.5% nonfat dry milk, 0.4% yeast extract, and 0.01% CaCl(2). The enzyme was produced extracellularly during the logarithmic phase of growth; no cell-bound activity was detected at any time. Partial purification of the maltase was accomplished by using diethylaminoethyl cellulose batch adsorption, ammonium sulfate precipitation, and Sephadex G-200 gel filtration. Maltase, isomaltase (oligo-1,6-glucosidase), and glucosyltransferase activities were purified 20.0-, 19.1-, and 11.5-fold, respectively. Some properties of the partially purified maltase were determined: optimum pH, 6.5; optimum temperature, 48 to 50 degrees C; pH stability range, 5.0 to 7.0; temperature stability range, 0 to 50 degrees C; isoelectric point, pH 5.2; and molecular weight, 52,000. The relative rates of hydrolysis of maltose (G(2)), maltotriose (G(3)), G(4), methyl-alpha-d-maltoside, G(40), dextrin, and isomaltose were 100, 22, 12, 10, 10, 8, and 5%, respectively; the K(m) on maltose was 5.8 mM; d-glucose, p-nitrophenyl-alpha-d-glucoside, and tris (hydroxymethyl) aminomethane were competitive inhibitors; transglucosylase activity of the enzyme on maltose resulted in the synthesis of isomaltose, isomaltotroise, and larger oligosaccharides.
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PMID:Extracellular Maltase of Bacillus brevis. 1634 94

Brettanomyces lambicus was isolated and identified from a typical overattenuating Belgian lambic beer and exhibited extracellular and intracellular alpha-glucosidase activities. Production of the intracellular enzyme was higher than production of the extracellular enzyme, and localization studies showed that the intracellular alpha-glucosidase is mostly soluble and partially cell wall bound. Both intracellular and extracellular enzymes were purified by ammonium sulfate precipitation, gel filtration (Sephadex G-150, Sephadex G-200, Ultrogel AcA-44), and ion-exchange chromatography (sulfopropyl-Sephadex C-50, (carboxymethyl-Sephadex C-50). The intracellular alpha-glucosidase exhibited optimum activity at 39 degrees C and pH 6.2. The extracellular enzyme exhibited optimum catalytic activity at 40 degrees C and pH 6.0. The molecular masses of purified intracellular and extracellular alpha-glucosidases, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, were 72,500 and 77,250, respectively. For both enzymes there was a decrease in the rate of hydrolysis with an increase in the degree of polymerization, and both enzymes hydrolyzed dextrins isolated from lambic wort (degrees of polymerization, 3 to 9 and more than 9). The K(m) values for p-nitrophenyl-alpha-d-glucopyranoside, maltose, and maltotriose for the intracellular enzyme were 0.9, 3.4, and 3.7 mM, respectively. The K(i) values for both enzymes were between 28.5 and 57 muM for acarbose and between 7.45 and 15.7 mM for Tris. These enzymes are probably involved in the overattenuation of spontaneously fermented lambic beer.
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PMID:Localization and Characterization of alpha-Glucosidase Activity in Brettanomyces lambicus. 1634 5

Lactobacillus brevis is found together with the yeast Brettanomyces lambicus during the overattenuation process in spontaneously fermented lambic beer. An isolated L. brevis strain has been shown to produce an alpha-glucosidase with many similarities to the glucosidase earlier found in B. lambicus. The enzyme was purified by ammonium sulfate precipitation, gel (Sephadex G-150 and Ultrogel AcA-44) filtration, and ion-exchange chromatography (DEAE-Sephadex A-50). The molecular weights of the enzyme, as determined by gel chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, were about 50,000 and 60,000, respectively. Optimum catalytic activity was obtained at 40 degrees C and pH 6.0. The enzyme showed a decrease of hydrolysis with an increase in the degree of polymerization of the substrate. The K(m) values for p-nitrophenyl-alpha-d-glucopyranoside, maltose, and maltotriose were 0.51, 3.0, and 5.2 mM, respectively. There was lack of inhibition by 0.15 mM acarbose and 0.5 M turanose, but the enzyme was inhibited by Tris (K(i) value of 25 mM). The alpha-glucosidase of L. brevis together with the enzyme of B. lambicus seems to be a key factor in the overattenuation of lambic beer, although the involvement of other lactic acid bacteria (pediococci) cannot be excluded.
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PMID:Localization and Characterization of alpha-Glucosidase Activity in Lactobacillus brevis. 1634 68


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