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)

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

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

Purified E. histolytica amylases III to VI were characterized by their hydrolytic behaviour towards 4-nitrophenyl alpha-malto-oligosaccharides, malto-oligosaccharides, amylose, amylopectin, glycogen and Y-cyclodextrin. The influence of specific inhibitors on the amylase activity of E. histolytica was examined and compared with typical alpha- and beta-amylases. Amylases III and IV showed alpha-glucosidase and glucosyltransferase activity by cleaving terminal non-reducing glucose from pNPG1 (III, IV) and pNPG2 to pNPG7 (III). Both enzymes were able to cleave malto-oligosaccharides and glucopolysaccharides to a large number of malto-oligosaccharides. Also transglucosidation reactions were observed, but maltose was not hydrolysed. Amylase V showed exoamylase-like properties by preferentially cleaving maltose units from the non-reducing end of synthetic and biogenic malto-oligosaccharides by a multiple-attack mechanism. Amylase VI was characterized as an alpha-amylase, showing great similarities with porcine pancreatic alpha-amylase in the hydrolysis pattern of 4-nitrophenyl alpha-malto-oligosaccharides and glucopolysaccharides. With biogenic malto-oligosaccharides amylase VI showed a transglucosidation reaction.
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PMID:Separation and characterization of four different amylases of Entamoeba histolytica. II. Characterization of amylases. 242 98

M-GTFI, originally screened as an inhibitor of Streptococcus mutans glucosyltransferase, strongly inhibited alpha-glucosidase, in a non-competitive manner especially when the synthetic substrate p-nitrophenyl-alpha-D-glucopyranoside was used. It also inhibited beta-glucosidase, beta-amylase and, to a lesser extent, beta-glucuronidase. The inhibitor was stable in neutral and alkaline pH ranges and dependency of the inhibition on pH and temperature was not observed. Some proteinases and polysaccharides-hydrolyzing enzymes as well as human saliva did not inactivate the inhibitor. There was a correlation between the release of sulfate anions from the inhibitor molecule on incubation with HCl (0.2 N) at 100 degrees C and loss of inhibitory properties of the molecule. It is suggested that the presence of sulfate ester linkages in the inhibitor molecule play an important role in the inhibition process.
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PMID:Characteristics of M-GTFI, a new inhibitor of Streptococcus mutans glucosyltransferase. 297 50

Acarbose is known to inhibit glucoamylase, maltase and sucrase. Our aim was to test whether it would also inhibit glucosyltransferase (GTF), to determine the type of inhibition and to compare the inhibitor potency of acarbose with that of nojirimycin and deoxynojirimycin, two other glucosidase inhibitors. Enzyme inhibition was measured either by chemical assay or by incorporation of radioactivity into product. Acarbose effectively inhibited the synthesis of polysaccharide by GTF from strains of Streptococcus mutans and Streptococcus sanguis, but not by fructosyltransferase from Streptococcus salivarius. Acarbose and 1-deoxynojirimycin were more potent inhibitors of GTF than maltose, nojirimycin or various amino sugars. The mechanism of action of these compounds is consistent with competitive inhibition.
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PMID:Inhibition by acarbose, nojirimycin and 1-deoxynojirimycin of glucosyltransferase produced by oral streptococci. 622 60

Lactobacillus acidophilus IFO 3532 was found to produce only intracellular alpha-glucosidase (alpha-D-glucoside glucohydrolase; EC 3.2.1.20). Maximum enzyme production was obtained in a medium containing 2% maltose as inducer at 37 degrees C and at an initial pH of 6.5. The enzyme was formed in the cytoplasm and accumulated as a large pool during the logarithmic growth phase. Enzyme production was strongly inhibited by 4 microM CuSO4, 40 microM CoCl2, and beef extract; MnSO4 and the presence of proteose peptone and yeast extract in the medium greatly enhanced enzyme production. A 16.6-fold purification of alpha-glucosidase was achieved by (NH4)2SO4 fractionation and DEAE-cellulose column chromatography. The enzyme showed high specificity for maltose. The Km for alpha-p-nitrophenyl-beta-D-glucopyranoside was 11.5 mM, and the Vmax for alpha-p-nitrophenyl-beta-D-glucopyranoside hydrolysis was 12.99 mumol/min per mg of protein. The optimal pH and temperature for enzyme activity were 5.0 and 37 degrees C, respectively. The enzyme activity was inhibited by Hg2+, Cu2+, Ni2+, Zn2+, Ca2+, Co2+, urea, rose bengal, and 2-iodoacetamide, whereas Mn2+, Mg2+, L-cysteine, L-histidine, Tris, and EDTA stimulated enzyme activity. Transglucosylase activity was present in the partially purified enzyme, and isomaltose was the only glucosyltransferase product. Amylase activity in the purified preparation was relatively weak, and no isomaltase activity was detected.
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PMID:Production and properties of alpha-glucosidase from Lactobacillus acidophilus. 641 77

beta-Fructofuranosidase, alpha-glucosidase, beta-glucosidase, alpha-mannosidase, beta-mannosidase, sucrose phosphorylase, glucosyltransferase and fructosyltransferase were separated by isoelectric focusing and sensitively detected to be slightly diffuse and insoluble spots in thin-layer gels, supported by a glass plate, by release of monosugars or a sugar phosphate, followed by conversion to glucose-6-phosphate (G6P) and then by reduction of NADP+ to NADPH, terminated by the formation of reduced Nitroblue Tetrazolium (NBT). Approximately 1-10 mU of enzyme was focused and the gel, after washing with a buffer, was partially dried and directly stained by uniformly spreading on the gel surface a staining medium containing sucrose or nitrophenyl glycosides as substrates, intermediary enzymes such as hexokinase, mutase and/or isomerase, NADP+, ATP, Mg+, phenazine methosulfate (PMS) and NBT. Specific staining procedures for each of these activities, on sucrose or on the glycosides as substrates, and staining procedures for multiple activities are described, with the conditions necessary for optimal development.
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PMID:Glucose, fructose, mannose and/or glucose-1-phosphate-releasing activity stains for glycosidases and glycosyltransferases in gels after isoelectric focusing. 751 61

Glycosidases and glycosyltransferases were electrophoresed in the presence of sodium dodecyl sulfate (SDS) in a thin-layer gel supported by a glass plate, treated with the nonionic detergent Triton X-100, and specifically stained for the sugar-releasing activity of these enzymes. Staining is based on conversion of monosugars or a sugar phosphate to glucose-6-phosphate by the appropriate intermediary enzymes, reduction of NADP+ to NADPH, and accumulation of reduced Nitroblue Tetrazolium in the gel. Among the enzymes tested, alpha-glucosidase, beta-glucosidase and beta-mannosidase could not be renatured, whereas beta-fructofuranosidase and alpha-mannosidase could be renatured unless heated before electrophoresis. Sucrose phosphorylase, glucosyltransferase and fructosyltransferase, which are single-peptide proteins with no cystine bond, could be renatured even after pretreatment with SDS and/or mercaptoethanol at 100 degrees C for 10 min. However, exclusive heating remarkably decreased the activities of these enzymes. Two-dimensional separation of the five renaturable enzymes was done in a single thin-layer gel, using SDS-electrophoresis in the first dimension and isoelectric focusing in the second dimension.
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PMID:Renaturation and activity staining of glycosidases and glycosyltransferases in gels after sodium dodecyl sulfate-electrophoresis. 752 70

We have previously reported that the imino sugar N-butyldeoxynojirimycin (NB-DNJ) inhibits glycolipid biosynthesis, in addition to its known activity as an inhibitor of the N-linked oligosaccharide processing enzyme alpha-glucosidase I. In an attempt to dissociate these two activities and identify an inhibitor which was more selective for the glycolipid biosynthetic pathway, several imino sugars have been N-alkylated and tested for inhibitory activity. The galactose analogue N-butyldeoxygalactonojirimycin (NB-DGJ) was found to be a potent inhibitor of glycolipid biosynthesis but in contrast to NB-DNJ had no effect on the maturation of N-linked oligosaccharides or on lysosomal glucocerebrosidase. The effect of increasing N-alkyl chain length on glycolipid inhibition was investigated. Nonalkylated DGJ, the N-methyl and N-ethyl derivatives, were noninhibitory. However, N-propylation resulted in partial inhibition while the N-butyl and N-hexyl derivatives resulted in maximal inhibition. Increasing alkyl chain length also resulted in increased potency of glucosyltransferase inhibition. In an in vitro Gaucher's disease model NB-DGJ was as effective as NB-DNJ in preventing glycolipid storage and may represent a more selective potential therapeutic agent than NB-DNJ for the management of this and other glycosphingolipidoses.
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PMID:N-butyldeoxygalactonojirimycin inhibits glycolipid biosynthesis but does not affect N-linked oligosaccharide processing. 792 54

The imino sugar deoxynojirimycin and its alkylated derivatives are inhibitors of the N-linked oligosaccharide processing enzymes alpha-glucosidase I and II. These compounds are glucose analogues and have the potential to inhibit both glucosidases and glucosyltransferases. However, to date there has been no report of deoxynojirimycin or similar analogues inhibiting a mammalian glucosyltransferase. We have investigated the effects of deoxynojirimycin and its alkylated derivatives on the biosynthesis of glycolipids in HL-60 cells. We have found that the N-butyl and N-hexyl derivatives of deoxynojirimycin, but not deoxynojirimycin itself, are novel inhibitors of the glucosyltransferase-catalyzed biosynthesis of glucosylceramide. This results in the inhibition of biosynthesis of all glucosylceramide-based glycosphingolipids. We have investigated the ability of one of these compounds, N-butyldeoxynojirimycin, to offset glucosylceramide accumulation in an in vitro Gaucher's disease model. This compound prevents lysosomal glycolipid storage and offers a novel therapeutic approach for the management of this and other glycolipid storage disorders.
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PMID:N-butyldeoxynojirimycin is a novel inhibitor of glycolipid biosynthesis. 813 59


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