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 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 high-molar mass form of beta-glucosidase from Aspergillus niger strain NIAB280 was purified to homogeneity with a 46-fold increase in purification by a combination of ammonium sulfate precipitation, hydrophobic interaction, ion-exchange and gel-filtration chromatography. The native and subunit molar mass was 330 and 110 kDa, respectively. The pH and temperature optima were 4.6-5.3 and 70 degrees C, respectively. The K(m) and kcat for 4-nitrophenyl beta-D-glucopyranoside at 40 degrees C and pH 5 were 1.11 mmol/L and 4000/min, respectively. The enzyme was activated by low and inhibited by high concentrations of NaCl. Ammonium sulfate inhibited the enzyme. Thermolysin periodically inhibited and activated the enzyme during the course of reaction and after 150 min of proteinase treatment only 10% activity was lost with concomitant degradation of the enzyme into ten low-molar-mass active bands. When subjected to 0-9 mol/L transverse urea-gradient-PAGE for 105 min at 12 degrees C, the nonpurified beta-glucosidase showed two major bands which denatured at 4 and 8 mol/L urea, respectively, with half-lives of 73 min.
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PMID:Purification and characterization of a beta-glucosidase from Aspergillus niger. 943 54

The beta-glucosidase from Rhizopus japonicus IFO5318 was purified by Ammonium sulfate salting out and column chromatographies with the recovery of 22%. The molecular weight of the enzyme was about 4.0 x 10(5), consisting of four identical subunits; The optimum reaction temperature and pH for the beta-glucosidase were 55 degrees C and pH 5.5, respectively; While the enzyme was sensitive to heat, it could be stable at a wide range of pH. The Km and Vmax values of the enzyme were 0.825 mg.ml-1 and 135.4 mumol.min-1.mg-1, respectively, using p-Nitrophenyl-beta-D-glucopyranoside as a substrate. The beta-glucosidase exhibited strongest hydrolysis effect on cellobiose and some of its activity could be inhibited by SDS, Fe3+ and Hg2+.
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PMID:[Purification and some properties of extracellular beta-glucosidase from Rhizopus japonicus IFO5318]. 1118 62

Ammonium sulfate (AS) fractionation is often used in protein and enzyme purification; however, the resultant protein pellets have a high salt content and desalting by dialysis is required prior to next analysis. Here, we have developed a phenol-based method for quick desalting and concentrating proteins after AS fractionation of complex olive leaf protein extract. After redissolving, AS precipitates were desalted with phenol extraction and the abundance of beta-glucosidase in each fraction was monitored with a specific antibody. The results of electrophoresis and Western blot showed the feasibility of the method. The method is quick and universal, and does not need much technique.
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PMID:Rapid desalting and protein recovery with phenol after ammonium sulfate fractionation. 1757 82