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)

This enzyme shows beta-D-glucosidase, beta-D-fucosidase and beta-D-galactosidase activities, all associated in a single peak in Sephadex G-200, DEAE-cellulose, concanavalin A-Sepharose chromatographies, and in high resolution isoelectric focusing (pI 4.56), having the optimal pH in the range 4.5-5.5. The enzyme is very stable under different conditions: (i) at pH in the range 5.5-7.0; (ii) in successive freezing-thawing cycles; (iii) at 4 degrees C; (iv) after exhaustive ultrasonic treatment. It is not stable beyond 40 degrees C, and in the presence of urea, Triton X-100, SDS or mercaptoethanol. HgCl2, KCN, Tris, maltose and the lactones were inhibitors of the enzyme. With glucose, fucose and galactose the inhibition is competitive. In addition, a transglycosylation mechanism seems to occur. The kinetic studies suggest a substrate-activation model and the presence of two primary active sites: fuco-gluco and galacto.
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PMID:Characterization and kinetics of beta-D-gluco/fuco/galactosidase from sheep liver. 641 26

An inducible endo-beta-1,6-glucanase was purified from Penicillium brefeldianum by DEAE-cellulose, Bio-Gel P-150 and high-pressure liquid chromatography. The final preparation was essentially free from beta-1,3-glucanase and beta-glucosidase activities. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis revealed one protein band with an Mr of 44000. The Vmax. and Km values were calculated to be 624 units (mumol/min)/mg and 2.78 mg/ml respectively. The glucanase had lytic activity against mycelial cells of the yeast Candida albicans. The yield of purified beta-1,6-glucanase from 100 mg dry weight of freeze-dried culture filtrate varied from 60 to 180 units.
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PMID:Purification and properties of a beta-1,6-glucanase from Penicillium brefeldianum. 650 37

Studies have been carried out on the activities and properties of the isozymes of alpha-mannosidase, alpha-glucosidase and beta-glucosidase in granulocytes, monocytes, lymphocytes and platelts from peripheral blood of heatlhy adult donors. The findings reveal the differences in activities as well as a characteristic distribution of the different molecular forms of these lysosomal hydrolases in specific cell types. Therefore, the results obtained with unfractionated total leukocyte smples from different subjects may vary according to the distribution of cell types in the circulation. Granulocytes and monocytes show only the acid alpha-mannosidase activity whereas lymphocytes and platelets show both acid and neutral activities. The specific activity of acid alpha-mannosidase in granulocytes and monocytes is higher than in lymphocytes and platelets. By DEAE-cellulose chromatography, the acid alpha-mannosidase in granulocyte and monocyte extracts elutes as two peaks, but only one peak is seen in lymphocytes. All cell types show both acid and neutral alpha-glucosidase activities. The specific activities of both isozymes are higher in granulocytes and monocytes than in lymphocytes and platelets. Monocytes show a higher acid than neutral activity. All other cell types show a higher neutral activity. Beta-Glucosidase in all cell types is mainly membrane-bound and it can be released by Triton X-100 and sodium taurocholate. Taurocholate also stimulates the beta-glucosidase activity of granulocytes, monocytes and lymphocytes whereas it inhibits the activity of this enzyme in platelets. These results indicate that variations in the total number of leukocytes and in the relative proportion of the various cell types in health and disease may yield inconsistent or unreliable values for enzyme activity in the diagnosis of lysosomal storage disease and in carrier detection.
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PMID:Studies on the activities and properties of lysosomal hydrolases in fractionated populations of human peripheral blood cells. 676 26

beta-Glucosidase activity was induced in Streptomyces venezuelae during growth on cellobiose, gentiobiose, salicin, methyl beta-glucoside, and p-nitrophenyl beta-D-glucopyranoside. Activity in cell extracts was separated by DEAE-cellulose chromatography into two fractions differing in substrate preference. One component showed higher activity with, and was more strongly induced by, cellobiose; the other showed greater activity and inducibility with salicin. Addition of glucose to cultures severely depressed induction of beta-glucosidase activity by cellobiose but not by salicin. Acetate and several amino acids inhibited induction by either substrate. The action of glucose was not reversed by cyclic AMP. Cultures of S. venezuelae using glucose, cellobiose, or a mixture of the two saccharides as their carbon source produced chloramphenicol during growth. In contrast with its effect on the induction of cellobiose activity, glucose did not suppress chloramphenicol production, indicating that the control mechanisms that establish carbon source preferences are not linked to those that regulate antibiotic biosynthesis in this organism.
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PMID:Glucose suppression of beta-glucosidase activity in a chloramphenicol-producing strain of Streptomyces venezuelae. 681 Nov 18

1. The kinetics of beta-D-fucosidase of the snail H. ericetorum have been studied. The enzyme shows beta-D-fucosidase, beta-D-glucosidase and beta-D-galactosidase activities, all associated in a single peak in both DEAE-cellulose chromatography and isoelectric focusing (p1 4.35), having the same optimal pH (5.0). 2. With the corresponding p-nitrophenyl glycosides as substrates, beta-D-fucosidase activity shows the lowest Km, the highest Vmax and the best Vmax/Km value; close activity values were obtained for beta-D-glucosidase, however, beta-D-galactosidase activity is much lower in this enzyme. 3. All the kinetic evidence suggests that this enzyme has two active sites: a fuco-gluco site and a galacto site. 4. beta-D-fucosidase and beta-D-glucosidase activities have similar Km, Vmax, Vmax/Km and Ki values; these values are very different from those of beta-D-galactosidase activity. beta-D-fucosides and beta-D-glucosides completely compete for a common active site in mixed-substrate experiments, while beta-D-galactosides only partially compete with both glycosides. 5. With delta-D-gluconolactone, the enzyme shows a hyperbolic mixed-type inhibition, mainly competitive for beta-D-fucosidase and beta-D-glucosidase activities (with the same inhibition sub-type), and predominantly non-competitive for beta-D-galactosidase activity (with different inhibition sub-type). With delta-D-gluconolactone more inhibition of beta-D-fucosidase and beta-D-glucosidase activities was found, and with gamma-D-galactonolactone, more inhibition of beta-D-galactosidase activity was detected. 6. The enzyme is activated by some carbohydrates, probably in relation with a transglycosylation mechanism.
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PMID:Kinetic evidence for two active sites in beta-D-fucosidase of Helicella ericetorum. 686 81

Homogenates of liver from cases of hepatic cirrhosis due to alpha 1-antitrypsin deficiency (PiZZ) alcoholism were analyzed for their content of various lysosomal enzymes. Also determined were the specific activities of lactate dehydrogenase, glutamate-oxaloacetate transaminase, glutamate-pyruvate transaminase, and creatine phosphokinase in the extracts of liver from cases of both kinds of hepatic cirrhosis: all of these activities were within the range of control values. Similarly, the specific activities of the following lysosomal hydrolases were unremarkable: acid phosphatase, beta-mannosidase, beta-fucosidase, beta-glucuronidase and beta-glucosidase. Hexosaminidase specific activity was increased twofold in livers from the cases of cirrhosis due to alpha 1-antitrypsin deficiency. The specific activity of alpha-mannosidase (measured at pH 4.5) in homogenates of livers from PiZZ individuals with cirrhosis and those with alcoholic cirrhosis was increased two- to four-fold. Chromatography of the high-speed supernatant fraction from homogenates of livers of cirrhotic and noncirrhotic individuals on columns of DEAE-cellulose resolved alpha-mannosidase activity into two components: under the conditions employed, acid pH optimum (pH 4.5) alpha-mannosidase did not bind to the resin, whereas intermediate pH optimum (pH 5.5) alpha-mannosidase could be eluted with 0.1 mol/l NaCl. Liver from one case of (PiZZ) alpha 1-antitrypsin deficiency and emphysema, without demonstrable cirrhosis, was found to contain normal levels of both acid alpha-mannosidase and intermediate alpha-mannosidase. However, cases of cirrhosis due to alpha 1-antitrypsin deficiency contained twice as much acid alpha-mannosidase and only one third to one fourth as much intermediate alpha-mannosidase as controls. The deficiency in hepatic intermediate alpha-mannosidase was also observed in 5 of 5 cases of alcoholic cirrhosis.
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PMID:Altered alpha-mannosidase isoenzymes in the liver in hepatic cirrhosis. 697 51

Glucosidase activities capable of removing the three glucose residues from Glc3Man9GlcNAc2 oligosaccharide were detected in a cell-free preparation of Saccharomyces cerevisiae X-2180. The glucosidase which cleaves the glucose residue at the nonreducing terminus (Glc3Man9GlcNAc2 oligosaccharide glucosidase) was equally distributed between the particulate and the supernatant fractions obtained after centrifugation of the yeast homogenate at 27,000 X g for 30 min. The membrane-bound activity was stimulated by Triton X-100, whereas the supernatant activity was not affected. The soluble Glc3Man9GlcNAc2 oligosaccharide glucosidase was partially purified from the supernatant by ammonium sulfate fractionation followed by DEAE-Sephadex chromatography. It was clearly separated from alpha-glucosidase, which acts onp-nitrophenyl-alpha-D-glucopyranoside, but still contained beta-glucosidase and alpha-mannosidase acting on p-nitrophenyl-beta-D-glucopyranoside and alpha-D-mannopyranoside, respectively. The Glc3Man9GlcNAc2 oligosaccharide glucosidase had a pH optimum of 6.8, and showed no requirement for divalent cations. The enzyme was very active with glucose-labeled Glc3Man9GlcNAc2, was slightly active with Glc2Man9GlcNAc2, and showed no activity with Glc1Man9GlcNAc2. These properties suggest that this enzyme is involved in the first step of processing of oligosaccharides after transfer from dolichyl pyrophosphate to proteins.
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PMID:Partial purification from Saccharomyces cerevisiae of a soluble glucosidase which removes the terminal glucose from the oligosaccharide Glc3Man9GlcNAc2. 701 69

The glycopeptidase preparation that has been isolated from almond emulsin and acts on beta-aspartylglycosylamine linkages in glycopeptides was separated into three active fractions by DEAE-cellulose column chromatography. The three discrete species of glycopeptidase (Groups A, B and C) have been purified 30-, 136-, and 99-fold, respectively. The optimum pH value of Group A was 6.0 and those of Groups B and C, 5.0. Isoelectric points of Groups A, B and C were pH 7.7, 8.6 and 8.7, respectively. All three glycopeptidases hydrolyzed quantitatively glycopeptides with 3-11 amino acid residues prepared from stem bromelain, ovalbumin and ovotransferrin. Group C preferred glycopeptides with shorter peptide chains, whereas Groups A and B preferred those with longer chains. Glycopeptidase Group A also hydrolyzed intact glycoproteins such as stem bromelain, ovalbumin, Taka-amylase A and desialylated human transferrin.
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PMID:Almond glycopeptidase acting on aspartylglycosylamine linkages. Multiplicity and substrate specificity. 721 57

1. A cellobiohydrolase component was isolated from a Penicillium funiculosum cellulase preparation by chromatography on DEAE-Sephadex, and purified by isoelectric focusing. 2. Purified in this way, the enzyme was homogeneous as judged by electrophoresis on sodium dodecyl sulphate/polyacrylamide gels and isoelectric focusing in polyacrylamide gels. 3. Acting in isolation, the enzyme had little hydrolytic activity to highly ordered celluloses such as cotton fibre, but, when recombined in the original proportions with the other components [endo-(1 leads to 4)-beta-D-glucanase and beta-D-glucosidase] of the complex, 98% of the original activity was recovered. 4. Synergistic effects were also observed when the enzyme was acting in concert with endo-(1 leads to 4)-beta-D-glucanase from other fungal sources. 5. Less-well-ordered celluloses, such as that swollen in H3PO4, were extensively hydrolysed, the principal product being cellobiose. 6. Attack on carboxymethyl-cellulose (CM-cellulose), which is the substrate normally used to assay for endo-(1 leads to 4)-beta-D-glucanase activity, was minimal. 7. The enzyme was associated with 9% of neutral sugar, 88% of which was mannose. It was isoelectric at pH 4.36 (4 degrees C) and had a mol.wt. of 46 300 (determined by gel chromatography on a calibrated column of Ultrogel). 8. The enzyme was specific for the beta-(1 leads to 4)-linkage.
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PMID:The isolation, purification and properties of the cellobiohydrolase component of Penicillium funiculosum cellulase. 745 6

The extracellular cellulase system of the white-rotting basidiomycete Ganoderma lucidum was characterised while growing in cellulose-containing shaken liquid culture. The protein content of the culture filtrate reached its maximum after 36 days and cellulase activity at about 60 days. Different cellulase activities (endoglucanase, cellobiohydrolase and beta-glucosidase) were determined in a range of pH extending from 6 to 2. All of the three enzyme activities have at least three peaks between pH 6 and 2, although optimum points of the different enzymes are slightly different, showing that the enzyme complex consists of a number of enzymes and isozymes. Partial purification of the enzyme complex was carried out by DEAE-cellulose column chromatography. Using 0-3 M linear urea gradient, protein was eluted in one sharp peak corresponding mainly to beta-glucosidase activity. Comparing crude extracellular protein with that of purified by the column using PAGE indicated that this method was suitable for the separation and partial purification of one type of Ganoderma cellulases.
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PMID:Some characteristics and partial purification of the Ganoderma lucidum cellulase system. 792 48


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