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

Electrophoretic data revealed the presence of various isozymes of endoglucanase and beta-glucosidase, the number of which varied from one to three in various species of the genus Aspergillus. pH 5.0 was optimum for all the isozymes whereas metal ion treatment showed complete inhibition of almost all the isozymes by Hg2+ and partial inhibition by Ca2+ and Co2+ of isozymes of both the enzymes. An alteration in the electrophoretic mobility of isozymes of beta-glucosidase was also noticed in some species with Hg2+ treatment.
 ...
PMID:Physical characterization of isozymes of endo-beta-1,4-glucanase and beta-1,4-glucosidase from Aspergillus species. 204 45

A facile isolation of beta-glucosidase (EC 3.2.1.21) from Escherichia coli containing the recombinant plasmid pNZ1001 carrying a beta-glucosidase gene from the extremely thermophilic anaerobic bacterium Tp8 is reported. The enzyme was purified to homogeneity by anion-exchange chromatography and steric exclusion HPLC following thermal denaturation/precipitation of heat-labile E. coli proteins. The enzyme had a broad specificity for beta-D-glucosides, galactosides, fucosides, and xylosides. Action on aryl-beta-D-glycosides of glucose, galactose, and fucose was characterized by low Km and high Kcat/Km values compared with disaccharide substrates for which specificity decreased in the order laminaribiose, sophorose, cellobiose, beta-gentiobiose, lactose. Galactono-1-4-lactone, glucono-1-5-lactone, and 1-O-methyl-beta-D-glucose were competitive inhibitors with Ki values of 1.6, 0.09, and 17.5 mM, respectively. The enzyme was remarkably stable to detergents, urea, and organic solvents. Thermostability was greatest at the pH activity optimum (pH 6.0-6.5) and half-life (t1/2) values were 11 min at 90 degrees C, 105 min at 85 degrees C, and 900 min at 80 degrees C. Activity was destabilized by Sr2+, Co2+, Ca2+, Mg2+, and Mn2+, but t1/2 increased in the presence of substrates or competitive inhibitors. Activation energy, Ea, was 54.3 kJ.mol-1. A free thiol group(s) was required for full activity, this being rapidly lost in the presence of Hg2+ or N-ethyl maleimide.
 ...
PMID:Stability and substrate specificity of a beta-glucosidase from the thermophilic bacterium Tp8 cloned into Escherichia coli. 312 75

Intracellular beta-glucosidase from Evernia prunastri has been purified to homogeneity using anion exchange on DEAE-Sephadex A-50, and gel filtration chromatography on Sephadex G-100 and Sepharose 6B. The purified beta-glucosidase showed a single protein band on native electrophoresis and its isoelectric point was at pH 3.12. The molecular mass, calculated from its partition coefficient on the Sepharose 6B column, was 311 kDa, being composed of several subunits of 60 and 70 kDa. The highest activity of this enzyme was attained at pH 4.0 and 60 degrees C. The enzyme showed strong resistance to thermal inactivation. Its activation energy was about 15 kJ/mol. Cellobiose, salicin, and p-nitrophenyl beta-D-glucoside, but not carboxymethylcellulose, were hydrolyzed by the enzyme, following substrate inhibition kinetics. The purified beta-glucosidase was considered a true cellobiase because of its great affinity towards cellobiose. Cellobiose inhibition does not seem to be a physiological phenomenon. Glucose inhibited enzyme activity in a competitive way (Ki = 1.26 mM). Fe3+ and Co2+ inhibited activity notably. Hg2+, Cu2+ and EDTA were practically ineffective. Even 200 mM gluconolactone did not affect enzyme activity.
 ...
PMID:Purification and characterization of a beta-glucosidase from Evernia prunastri. 313 29

An extracellular beta-glucosidase (EC 3.2.1.21) was purified from culture filtrate of the anaerobic rumen fungus Orpinomyces sp. strain PC-2 grown on 0.3% (wt vol-1) Avicel by using Q Sepharose anion-exchange chromatography, ammonium sulfate precipitation, chromatofocusing ion-exchange chromatography, and Superose 12 gel filtration. The enzyme is monomeric with a M(r) of 85,400, as estimated by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, has a pI of 3.95, and contains about 8.5% (wt vol-1) carbohydrate. The N terminus appears to be blocked. The enzyme catalyzes the hydrolysis of cellobiose and p-nitrophenyl-beta-D-glucoside (PNPG). The Km and Vmax values with cellobiose as the substrate at pH 6.0 and 40 degrees C are 0.25 mM and 27.1 mumol.min-1 x mg-1, respectively; with PNPG as the substrate, the corresponding values are of 0.35 mM and 27.7 mumol.min-1 x mg-1. Glucose (Ki = 8.75 mM, with PNPG as the substrate) and gluconolactone (Ki = 1.68 x 10(-2) and 2.57 mM, with PNPG and cellobiose as the substrates, respectively) are competitive inhibitors. Optimal activity with PNPG and cellobiose as the substrates is at pH 6.2 and 50 degrees C. The enzyme has high activity against sophorose (beta-1,2-glucobiose) and laminaribiose (beta-1,3-glucobiose) but has no activity against gentiobiose (beta-1,6-glucobiose). The activity of the beta-glucosidase is stimulated by Mg2+, Mn2+, Co2+, and Ni2+ and inhibited by Ag+, Fe2+, Cu2+, Hg2+, SDS, and p-chloromercuribenzoate.
 ...
PMID:Isolation and properties of an extracellular beta-glucosidase from the polycentric rumen fungus Orpinomyces sp. strain PC-2. 811 94

Three cellobiases, here called cellobiase A, B, and C, from the culture filtrate of Aspergillus niger A20, were purified by precipitation with ammonium sulphate, gel filtration through Sephadex G-75, and column chromatography of DEAE-cellulose. The purified enzymes were homogeneous on polyacrylamide disk electrophoresis. The mol wt of the purified enzymes were estimated by SDS-gel electrophoresis to be 88,000, 80,000, and 71,000 for cellobiases A, B, and C, respectively. The enzymes were active at pH 4.5 and 55-60 degrees C. The pattern of their amino acid compositions showed high contents of aspartic acid, glutamic acid, threonine, serine, and glycine. The apparent K(m) values for cellobiose were 0.9, 1.63, and 1.0 mM for cellobiases A, B, and C, respectively. Calcium ions stimulated cellobiases B and C, and Co2+ and Mg2+ ions stimulated cellobiase A. The purified enzymes hydrolyzed cellobiose and aryl-beta-D-glucosides, but they had no action on sucrose, maltose, and cellulose. The three cellobiases catalyzed transglycosylase reaction, and the major product formed from cellobiose was tetramer of glucose.
 ...
PMID:Purification and properties of three cellobiases from Aspergillus niger A20. 1032 88

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.
 ...
PMID:Production of cellulase by Trichoderma reesei from dairy manure. 1549 32