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)

A beta-glucosidase of Coccidioides immitis was identified in electrophoresis gel separations of the concanavalin A-bound mycelial culture-filtrate-plus-lysate preparation. p-Nitrophenol-beta-D-glucopyranoside was used as the substrate to visualize the enzymatically active fraction in nonreducing gels. The gel-isolated, chromatographically purified enzyme has an optimal pH of 8.0 and cleaves beta-1,3-glycosyl linkages. The alkaline beta-glucosidase was further characterized by a pI of 3.8 to 4.0, optimal activity at 37 to 40 degrees C, and molecular size of 120 kDa as identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified beta-glucosidase is identical to a previously reported 120-kDa antigen (Ag) which reacts with immunoglobulin M (IgM) tube precipitin (TP) antibody in sera from patients with coccidioidomycosis. The TP-Ag was described as a valuable serodiagnostic reagent for detection of specific IgM in patients with early coccidioidal infections. The beta-glucosidase, like the TP-Ag, was localized in the cell wall and cytoplasmic vesicles of parasitic cells (spherules) by immunofluorescence and immunoelectron microscopy with specific antiserum raised against the purified enzyme. The boiled cell wall fraction isolated from these same young (presegmented) spherules was partially digested by the beta-glucosidase. Addition of a potent beta-glucosidase inhibitor, 1-deoxynojirimycin, to the parasitic-phase culture medium at a concentration of 200 microM blocked or retarded conversion of arthroconidia to spherules. Antibody was raised in guinea pigs against chromatographically purified 1-deoxynojirimycin which was conjugated with bovine serum albumin. The inhibitor was localized by immunofluorescence in the wall of the 1-deoxynojirimycin-treated cells. We suggest that the spherule wall-associated, alkaline hydrolase functions as a beta-1,3-glucanase to provide for wall plasticity as well as intussusception of newly synthesized wall polymers during the period of rapid diametric growth of parasitic cells of C. immitis.
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PMID:A seroreactive 120-kilodalton beta-1,3-glucanase of Coccidioides immitis which may participate in spherule morphogenesis. 139 46

Glycosidases are lysosomal enzymes that participate in the catabolism of glycoproteins and other glycoconjugates, and in some way may modify their activity in situations in which carbohydrate metabolism could be altered, such as the case of obesity. Using a fluorometric assay, a study was made of four glycosidase activities: N-acetyl-beta-D-hexosaminidase (NAG), alpha-mannosidase and alpha- and beta-glucosidase in the serum, pancreas, liver and kidney of 22 Zucker fa/fa genetically obese rats and of 23 fa/? controls, both with ages ranging between 13 and 15 weeks. After 12-14 hours fast and prior anaesthesia with sodium pentobarbital intraperitoneally, blood and the afore-mentioned organs were removed for enzymatic study of the serum and the organs after homogenization and centrifugation. In the serum a statistically significant increase in alpha-mannosidase (p < 0.0001) and alpha-glucosidase (p < 0.02) activities was found in the fa/fa obese rats as compared with the controls. No statistically significant differences were found in serum hexosaminidase activity between the two groups, and no serum beta-glucosidase enzymatic activity was detected. In liver, a decrease was observed in hexosaminidase (p < 0.002) and alpha-glucosidase (p < 0.01) activities in the obese rats as compared with the controls. In whole pancreas an increase was found in alpha-glucosidase activity in the obese rats with respect to the controls (p < 0.001), with no statistically significant differences in the hexosaminidase, alpha-mannosidase and beta-glucosidase activities.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Enzymatic glycosidase activities in experimental obesity. 142 11

The intercellular lipids of the stratum corneum, which are highly enriched in ceramides, are critical for the mammalian epidermal permeability barrier. During the terminal stages of epidermal differentiation, the glucosylceramide content is dramatically reduced, while the content of free ceramides increases. To investigate whether beta-glucocerebrosidase (beta-GlcCer'ase) could be responsible for this change in lipid content, we characterized its activity in murine epidermis, compared enzyme activity to other murine tissues, and localized beta-GlcCer'ase activity within the epidermis. Epidermal extracts demonstrated linear 4-methylumbelliferyl-beta-D-glucose hydrolysis (to 3 h) with protein concentrations between 1 and 250 micrograms/ml. Whole epidermis contained comparable beta-glucosidase activity (9.1 +/- 0.4 nmol/min per mg DNA) to murine brain and liver, and 5-fold higher activity than spleen. Epidermal beta-glucosidase activity was stimulated greater than 15-fold by sodium taurocholate at pH 5.6, and inhibited at acidic pH (3.5-4.0). Bromoconduritol B epoxide (greater than or equal to 1.0 microM), inhibited epidermal enzyme activity by greater than 75%, while activity in brain, liver, and spleen was only inhibited by 6, 17, and 14%, respectively. Moreover, beta-GlcCer'ase mRNA expression in murine epidermis exceeded levels in liver, brain, and spleen. Finally, beta-GlcCer'ase activity was highest in the outer, more differentiated epidermal cell layers including the stratum corneum. In summary, mammalian epidermis contains an usually high percentage (approximately 75%) of beta-glucocerebrosidase activity, and the concentration of activity in the more differentiated cell layers may account for the replacement of glucosylceramide by ceramides in the outer epidermis.
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PMID:beta-Glucocerebrosidase activity in murine epidermis: characterization and localization in relation to differentiation. 143 99

beta-Glucosidase from Curvularia lunata was immobilized in pellets of polyacrylamide, sodium alginate and agar. The activity of the enzyme was estimated at different times by measuring the absorbance of a solution into which 2-nitrophenol was released by the enzyme. The effect of pH and temperature was studied to select the optimum conditions. Thermostability of the beta-glucosidase in each of the carriers was assessed over a period of 12-26 d. The immobilized enzyme on all the three carriers retained its activity longer than free enzyme did. Polyacrylamide was the best carrier both in terms of thermostability and of reusability of the immobilized enzyme preparations. The Michaelis constant (Km) for each of the immobilized enzyme preparation was calculated.
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PMID:Immobilized beta-glucosidase from Curvularia lunata. 145 95

Genomic DNA fragments encoding beta-glucosidase activities of the thermophilic actinomycete Microbispora bispora were cloned into Escherichia coli. Transformants expressing beta-glucosidase activity were selected by their ability to hydrolyze the fluorogenic substrate 4-methylumbelliferyl-beta-D-glucoside. Two genes encoding beta-glucosidase activity were isolated and distinguished by restriction analysis, Southern hybridization, and the substrate specificities of the encoded enzymes. One gene, bglB, encoded a beta-glucosidase that was expressed intracellularly in E. coli. It exhibited a molecular mass of approximately 52,000 Da by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE) and 51,280 Da by nondenaturing gradient PAGE, a pI of 4.6, and temperature and pH optima of 60 degrees C and 6.2, respectively. Cloned BglB showed greater activity against cellobiose than against aryl-beta-D-glucosides and was thermostable, retaining about 70% of its activity after 48 h at 60 degrees C. BglB activity is activated two- to threefold in the presence of 2 to 5% (0.1 to 0.3 M) glucose. The DNA sequence of the 2.2-kb insert carrying bglB has been determined. An open reading frame which codes for a protein of 473 amino acids with a predicted molecular mass of 52,227 Da showed significant homology (40 to 47% identity) with beta-glucosidases from glycosal hydrolase family 1.
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PMID:Cloning, characterization, and nucleotide sequence of a gene encoding Microbispora bispora BglB, a thermostable beta-glucosidase expressed in Escherichia coli. 148 72

Although beta-D-fucosidase (beta-D-fucohydrolase, EC 3.2.1.38) has been isolated from various sources, all those enzymes were associated with a high activity of beta-D-galactosidase and/or beta-D-glucosidase. We have purified a specific beta-D-fucosidase in electrophoretically homogeneous form from crude extracts of Aspergillus phoenicis by polyethyleneglycol 8000-phosphate buffer aqueous two-phase separation, and successive chromatography on DEAE-Sephadex A-50, hydroxyapatite, and Sephadex G-100 columns. The molecular weight of the enzyme was estimated to be 57,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 50,000 to 60,000 by gel filtration on Sephadex G-100. The enzyme showed optimum activity at pH 6.0 and 40 degrees C; it was stable in the pH range 5.5-6.5 and below 35 degrees C. The Km and the Vmax values for pNP-beta -D-fucoside were 2.4 mM, and 12.8 mumol.min-1.mg-1, respectively. The enzyme was strongly inhibited by sulfhydryl group reagents, p-chloromercuribenzoate, n-ethylmaleimide, and iodoacetate. It was also inhibited by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, diethyl pyrocarbonate, and N-bromosuccinimide. Thus, -SH and -COOH groups and histidyl and tryptophyl residues were essential for enzyme activity. The purified beta-D-fucosidase showed high specificity toward p-nitrophenyl-beta-D-fucoside. The enzyme was inhibited by D-fucose and D-fucono-gamma-lactone, but not by D-galactose, D-galactono-gamma-lactone, D-glucose, or D-glucono-gamma-lactone; the latter compounds are specific inhibitors of beta-D-galactosidase and beta-D-glucosidase, respectively. Thus, this enzyme is the most strictly specific beta-D-fucosidase when compared with those previously reported.
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PMID:Purification and characterization of a strictly specific beta-D-fucosidase from Aspergillus phoenicis. 152 31

Pseudorabies virus hemagglutinin was readily adsorbed on mouse erythrocytes at 4, 22, or 37 degrees C, but not on cattle erythrocytes. The adsorbed hemagglutinin could not be eluted from the cells by resuspending in phosphate-buffered saline (PBS), by incubating at 37 or 50 degrees C, or by incubating in the presence of neuraminidase. The receptor on mouse erythrocytes for the hemagglutinin was inactivated by trypsin, but not by neuraminidase, sodium deoxycholate (DOC), potassium periodate (KIO4), dithiothreitol (DTT), 2-mercaptoethanol (2-ME) and formalin. The hemagglutinin was inactivated by trypsin, alpha-amylase, pepsin, DOC, KIO4, and ethylendiamine-tetraacetic acid (EDTA), but not by papain, beta-glucosidase, phospholipase C, neuraminidase, DTT, 2-ME, Tween-80, ethylether, chloroform, trichloro-trifluoroethane, beta-propiolactone and formalin, suggesting that the hemagglutinin active component involved glycoproteins. The hemagglutinin was stable at 37 degrees C for lower temperatures but not at 60 degrees C or higher. The hemagglutinin activity was resistant to ultraviolet irradiation, while the infectivity was very susceptible. The hemagglutinin and the infectivity were readily sedimented by ultracentrifugation at 48,000 x g for 3 hr. In rate zonal centrifugation of the preparation on a sucrose density gradient, the hemagglutination (HA) activity showed a sharp peak at 1.22 g/ml coinciding with the peak of infectivity. The HA activity in the peak fraction seemed to be structually associated with virus particles. After fractionation of the virus by Nonidet P-40, the HA activity was found only in the fraction of the envelope material, indicating that the hemagglutinin is situated in the viral envelop.
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PMID:Physicochemical properties of pseudorabies virus hemagglutinin. 166 85

Fifteen different cellulase preparations from Trichoderma reesei, obtained either commercially or from pilot plants, were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting using monoclonal antibodies against two cellobiohydrolases (CBH I, CBH II), an endoglucanase (EG I), and beta-glucosidase. The staining patterns were compared with the activities of the preparations against filter paper (FPU), carboxymethylcellulose (CMC-ase), cellobiose (beta-glucosidase), and azocasein (protease). Variable amounts of proteolytic degradation products of CBH I, CBH II, and EG I were seen in most samples, and only half of them contained intact beta-glucosidase. The degree of proteolysis did not correlate with any significant difference in the respective activities of these preparations against filter paper cellulose or carboxymethylcellulose. In more than 50% of all cases a decreased beta-glucosidase activity and the absence of intact beta-glucosidase protein in Western blots was observed in preparations displaying high proteolytic activity.
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PMID:Characterization of commercial Trichoderma reesei cellulase preparations by denaturing electrophoresis (SDS-PAGE) and immunostaining using monoclonal antibodies. 177 16

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

A beta-glucosidase with cellobiase activity was purified to homogeneity from the culture filtrate of the mushroom Termtomyces clypeatus. The enzyme had optimum activity at pH 5.0 and temperature 65 degrees C and was stable up to 60 degrees C and within pH 2-10. Among the substrates tested, p-nitrophenyl-beta-D-glucopyranoside and cellobiose were hydrolysed best by the enzyme. Km and Vm values for these substrates were 0.5, 1.25 mM and 95, 91 mumol/min per mg, respectively. The enzyme had low activity towards gentiobiose, salicin and beta-methyl-D-glucoside. Glucose and cellobiose inhibited the beta-D-glucosidase (PNPGase) activity competitively with Ki of 1.7 and 1.9 mM, respectively. Molecular mass of the native enzyme was approximated to be 450 kDa by HPLC, whereas sodium dodecyl sulphate polyacrylamide gel electrophoresis indicated a molecular mass of 110 kDa. The high molecular weight enzyme protein was present both intracellularly and extracellularly from the very early growth phase. The enzyme had a pI of 4.5 and appeared to be a glycoprotein.
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PMID:Purification and characterisation of a beta-glucosidase (cellobiase) from a mushroom Termitomyces clypeatus. 190 Jan 98


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