Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.21 (beta-glucosidase)
 3,280 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The optimal reaction conditions and kinetic properties of eleven leukocyte acid hydrolases determined with the use of fluorigenic derivatives of 4-methyl-umbelliferone are described. The enzymes studied were acid phosphatase, aryl sulfatase, alpha- and beta-glucosidase, alpha- and beta-galactosidase, alpha-mannosidase, N-acetyl-beta-glucosaminidase, N-acetyl-beta-galactosaminidase, beta-glucuronidase and alpha-fucosidase. More than 90% of the activity of each enzyme was released into a 27,000 X g supernatant by a double sonication procedure employing 0.9% sodium chloride and 0.1% Triton X-100. The Km values obtained were similar to those previously reported for chromogenic subtrates. A single Km value could not be derived for beta-galactosidase because its double reciprocal plot was not linear. All enzymes could be measured with less than 10 mug of protein within 15 min. Activators and inhibitors studied included the chloride salts of Na+, K+, Zn2+, Ca2+, Mg2+, Hg2+, and Fe2+ as well as p-chloromercuriphenysulfonate, glutathione, BAL, EDTA, EGTA, Triton X-100 and sodium taurocholate. The reaction conditions described in this report can be used for the diagnosis of various lysosomal storage diseases and should facilitate the development of automated procedures for the analysis of these eleven enzyme activities with small quantities of blood.
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PMID:Human leukocyte acid hydrolases: characterization of eleven lysosomal enzymes and study of reaction conditions for their automated analysis. 0 26

A constitutive beta-glucosidase of Erwinia herbicola Y46 was studied as a prerequisite to an assessment of its significance in the release of bacteriotoxic aglycones from plant beta-glucosides, and the possible effects of the aglycones on the course of such plant diseases as "fire-blight". The enzyme was purified 86.5-fold from crude extracts of cells grown on yeast beef broth. Ammonium sulfate precipitation, DEAE-cellulose fractionation, and gel filtration through Sephadex G-100 resulted in a preparation having one peak of activity on isoelectrofocussing, on gel filtration through Sephadex G-200, and on polyacrylamide gel electrophoresis. The latter techniques demonstrated, in addition to the major protein band associated with activity, a single minor impurity. The enzyme was active against p-nitrophenyl-beta-glucoside (p-NPG) and phloridzin, but showed only very slight activity against salicin and arbutin, and no detectable activity against beta-methyl-D-glucoside, cellobiose, lactose, and esculin. The production of beta-glucosidase was maximum at the late log phase of growth on yeast beef broth medium and declined somewhat thereafter. The incorporation of inducers (carbohydrates) in defined basal medium resulted in only small variations in specific activity in the resulting cells; The activity (p-NPG substrate) was not inhibited by D-glucose, phloretin, esculin, salicin, arbutin, lactose, or cellobiose, but was slightly inhibited by 1.0 mM phloridzin. Slight inhibition was observed in the presence of sulfhydryl reagents (iodoacetamide, p-chloromercuribenzoate), but sodium azide, ethylene-diaminetetraacetic acid, Cu2+, and Zn2+ ions produced no effect. The activity was stable, in both crude and purified preparations, over the pH ranges 6.0-7.5 (100% activity) and 4.5-greater than 8.5 (50% activity). The enzyme retained 80% activity after 30 min at 50 degrees C, but only 25% after 30 min at 60 degrees C. The enzyme had a mean K-m value (phloridzin) of 1.35 times 10-4 M, an isoelectric point of 4.75, a molecular weight, determined by Sephadex G-200 gel filtration, of about 122 000, and an optimum pH for activity of 6.5-7.0.
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PMID:Partial purification and properties of a beta-glucosidase from Erwinia herbicola Y46. 23 59

The yeast alpha-mannosidase [EC 3.2.1.24] was purified 1160-fold from the crude extract of the autolysate. The purified preparation was practically free from alpha-glucosidase, beta-glucosidase, alpha-galactosidase, beta-galactosidase, beta-mannosidase, and beta-N-acetylhexosaminidase activities. After the separation of yeast mannan during the purification procedures the enzyme became unstable but could be stored at 5 degrees C for three weeks with 50% loss of activity. The purified enzyme hydrolyzed both aryl and alkyl mannosides, but hydrolysis of yeast mannan proceeded slowly. Yeast mannan and Zn2+ increased the enzyme catalyzed hydrolysis of p-nitrophenyl mannoside, whereas NaN3, monoiodoacetate and methyl alpha-D-mannoside acted as inhibitors. The molecular weight was estimated to be 450,000 by gel filtration.
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PMID:Purification and properties of alpha-mannosidase from bakers' yeast. 33 3

A new type of glycopeptidase hydrolyzing beta-aspartylglycosylamine linkages was partially purified from almond emulsin by chromatography on Sephadex G-200 and DE 52. The enzyme degraded stem bromelain glycopeptide, Asn-Asn(Man3,Xyl1,Fuc1,GlcNAc2)-Glu-Ser-Ser, to yield equimolar amounts of intact oligosaccharide, peptide (Asn-Asp-Glu-Ser-Ser), and ammonia. The Km value for the stem bromelain glycopeptide was 4 mM, and the optimum pH was 5.2. The enzyme was markedly inhibited by 10 mM Cu2+, Fe3+, and Zn2+. Thiol inhibitors and actinomycete protease inhibitors had no effect. The glycopeptides used as substrates were prepared from stem bromelain, ovalbumin or ovotransferrin. The enzyme hydrolyzed glycopeptides with 3-11 amino acid residues, whereas it did not hydrolyze glycopeptides with 1-2 amino acid residues. Furthermore, Asn-oligosaccharide was not inhibitory to the enzyme.
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PMID:Some characteristics of a new glycopeptidase acting on aspartylglycosylamine linkages. 73 97

The effects of dietary fat and dietary fiber (DF) levels in diet on fecal flora, activities of three fecal enzymes, putrefactive metabolites, fecal mutagenicity and fecal properties were studied in eight healthy volunteers. They were given low fat and low DF diet (LF: fat energy ratio was 13.9%, and DF intake was 9.0 g/day) for 10 days, high fat and low DF diet (HF: fat energy ratio was 52.7%, and DF intake was 7.1 g/day) for 10 days, and high fat and high DF diet (HFF: fat energy ratio was 52.0%, and DF intake was 24.8 g/day) for 10 days. No change of fecal flora at the bacterial group level was observed throughout the experimental period, except that the population of lactobacilli showed a tendency to increase in HF period. Fecal activities of beta-glucuronidase, beta-glucosidase and nitroreductase and some putrefactive products were unchanged between LF and HF, while these values decreased in HFF period. No significant change of fecal properties was observed between LF and HF, while by HFF supplementation fecal weight increased and fecal pH value was lower than that in LF and HF. Excretions of iron, zinc and calcium in feces did not increase by high DF supplementation.
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PMID:Effect of dietary fat and fiber on fecal flora, bacterial metabolites, and fecal properties in Japanese volunteers. 133 9

Beta-N-Acetylglucosaminidase has been purified from an acetone extract of Aspergillus niger. The protein has a Mr = 149,000. It contains neither Mn2+, Zn2+, nor cysteine and exhibits no cation requirement for activity. Isoelectric focusing separates two isozymes; the major isoenzyme has a pI = 4.4. Both isozymes exhibit beta-N-acetylgalactosaminidase and beta-glucosidase, as well as glucosaminidase activity. The mechanism of action of this enzyme has been studied in detail using a variety of substrate structure/activity and kinetic experiments. Rate data plotted versus pH depends on the following ionization constants, respectively: for pKm, 2.95; for log Kcat, 7.6; and for log kcat/Km, 2.95 and 8.25. The kcat value of H2O/D2O for p-nitrophenyl-beta-N-acetylglucosaminide hydrolysis is 1.27 at pH 4.6 and 1.00 at pH 7.0. The rho value for the hydrolysis of para-substituted phenylglucosaminides is +0.36; rho for the hydrolysis of fluoro-substituted N-acetyl derivatives is -1.41. Two sulfur-containing substrate analogues, the 1-thioglucosaminide, and the N-thioacetyl derivative, exhibit either no or little substrate activity. The hydrolysis of the 2,4-dinitrophenyl-glucosaminide is not biphasic as indicated by stopped flow kinetic studies. These several results are interpreted to show that: 1) enzymatic nucleophilic catalysis is not employed by beta-N-acetylglucosaminidase; 2) the glycosidic oxygen is protonated very early in the reaction, perhaps even in the Michaelis complex; 3) the acetamido oxygen provides anchimeric assistance to hydrolysis via charge stabilization of the oxocarbonium ion (or via oxazoline formation); 4) additional charge stabilization is provided by an enzymic anion, perhaps a side chain carboxylate group. The role of the acetamido group is discussed and comparisons are made between lysozyme, beta-galactosidase, and beta-N-acetylglucosaminidase.
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PMID:Purification, properties, kinetics, and mechanism of beta-N-acetylglucosamidase from Aspergillus niger. 744 May 73

Inhibition of beta-glucosidase activity by Cu(II), Zn(II) and Ni(II) was investigated as a function of pH and buffer type. Both factors were found to exert a strong effect on the activity of the enzyme. All three of the investigated heavy metals inhibited the enzyme activity in acetate buffer. At metal concentrations of 0.6 mM, Zn and Ni reduced the enzyme activity by 25-30% under optimal pH conditions (pH 5-5.2). Under the same conditions, Cu showed an even more pronounced inhibitory effect than Zn and Ni. In presence of 0.6 mM Cu, the enzyme activity was lowered by more than 90% in comparison to metal free systems. In contrast to these results, no enzyme inhibition was observed in citrate buffer, even in the presence of 1 mM Cu. The inhibition of beta-glucosidase activity by Cu increased with increasing pH. Inhibition by Zn and Ni was less pH-dependent in the observed pH range (pH 4-5.5). Copper caused a distinct shift in the pH optimum of enzyme activity, whereas this was not the case for Zn or Ni. The effects of buffer and pH on enzyme inhibition by Cu, Zn and Ni were successfully described using a chemical speciation model, based on the assumption that enzyme activity depends on the protonation of the amino acids at the reactive site and that enzyme activity is inhibited by complexation of the reactive sites by the heavy metal cations. The results show the importance of taking chemical conditions and speciation into account when investigating the effect of heavy metal cations on biological systems.
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PMID:Heavy metal effects on beta-glucosidase activity influenced by pH and buffer systems. 1048 47

Cellulase production by the fungi Trichoderma reesei was studied using dairy manure as a substrate. Data showed that T. reesei RUT-C30 had higher cellulase production than T. reesei QM 9414 and that a homogenized manure, treated by a blender to reduce fiber size, led to higher cellulase production. The cellulase production was further optimized by growing T. reesei RUT-C30 on homogenized manure. The effects of manure concentration, pH, and temperature on cellulase production were investigated with optimal parameter values determined to be 10 g/l manure (dry basis), 25.5 degrees C, and pH 5.7, respectively. Elimination of CaCl2, MgSO4, nitrogen sources (NH4+ and urea) and trace elements (Fe2+, Zn2+, Co2+ and Mn2+) from the original salt solution had no negative influence on the cellulase production, while phosphate elimination did reduce cellulase production. Based on above results, the final medium composition was simplified with manure additives being KH2PO4, tween-80 and CoCl2 only. Using this medium composition and a reaction time of 6-8 days, a maximum cellulase production activity of 1.74 IU/ml of filter paper activity, 12.22 IU/ml of CMCase activity, and 0.0978 IU/ml of beta-glucosidase was obtained. This filter paper activity is the highest ever reported in cellulase production from agricultural wastes.
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PMID:Production of cellulase by Trichoderma reesei from dairy manure. 1549 32

[reaction: see text] A new synthesis of (+)-cyclophellitol, a potent beta-glucosidase inhibitor, has been completed in nine steps from D-xylose. The key transformations involve a zinc-mediated fragmentation of benzyl-protected methyl 5-deoxy-5-iodo-xylofuranoside followed by a highly diastereoselective indium-mediated coupling with ethyl 4-bromocrotonate. Subsequent ring-closing olefin metathesis, ester reduction, olefin epoxidation, and deprotection then afford the natural product. This constitutes the shortest synthesis of (+)-cyclophellitol reported to date.
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PMID:A short synthesis of (+)-cyclophellitol. 1629 57

Rice (Oryza sativa) BGlu1 beta-glucosidase was expressed in Escherichia coli with N-terminal thioredoxin and hexahistidine tags and purified by immobilized metal-affinity chromatography (IMAC). After removal of the N-terminal tags, cation-exchange and S-200 gel-filtration chromatography yielded a 50 kDa BGlu1 with >95% purity. The free enzyme and a complex with 2,4-dinitrophenyl-2-deoxy-2-fluoro-beta-D-glucopyranoside inhibitor were crystallized by microbatch and hanging-drop vapour diffusion. Small tetragonal crystals of BGlu1 with and without inhibitor grew in 18%(w/v) PEG 8000 with 0.1 M sodium cacodylate pH 6.5 and 0.2 M zinc acetate. Crystals of BGlu1 with inhibitor were streak-seeded into 23%(w/v) PEG MME 5000, 0.2 M ammonium sulfate, 0.1 M MES pH 6.7 to yield larger crystals. Crystals with and without inhibitor diffracted to 2.15 and 2.75 angstroms resolution, respectively, and had isomorphous orthorhombic unit cells belonging to space group P2(1)2(1)2(1).
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PMID:Purification, crystallization and preliminary X-ray analysis of rice BGlu1 beta-glucosidase with and without 2-deoxy-2-fluoro-beta-D-glucoside. 1688 May 61


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