Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

An intracellular beta-glycoside hydrolase with beta-glucosidase and beta-galactosidase activity, designated beta-glucosidase BGL1, was isolated to apparent homogeneity from the thermophilic ascomycete Talaromyces thermophilus CBS 236.58. The monomeric enzyme has a molecular mass of 50 kDa (SDS-PAGE) and an isoelectric point of 4.5-4.6. The enzyme is active with both glucosides such as cellobiose and galactosides including lactose; based on the catalytic efficiencies determined glucosides are the preferred substrates. beta-Galactosidase activity of BGL1 is activated by various mono and divalent cations including Na+, K+ and Mg2+, and it is moderately inhibited by its reaction products glucose and galactose. Its pH optimum for the hydrolysis of galactosides is in the range of 5.5-6.0, and its optimum temperature was found to be 50 degrees C (15 min assay). In addition to its hydrolytic activity, BGL1 shows a significant transferase activity which results in the formation of galacto-oligosaccharides. These have recently attracted interest because of possible applications in food industry. The highest yields of oligosaccharides was approximately 20% when using 38 gl(-1) lactose as the starting material.
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PMID:Purification and characterisation of an intracellular enzyme with beta-glucosidase and beta-galactosidase activity from the thermophilic fungus Talaromyces thermophilus CBS 236.58. 1644 2

Chaetomium thermophilus CT2 was a cellulolytic fungus. It was a widely-existing saprophyte, which grower rapidly in soil. The cellulases synthesized by C. thermophilus CT2 was overall, consisting of three principal types of enzymes. The cellobiohydrolase was one of these three cellulases, which was associated with the endo-beta-1,4-glucanase and beta-glucosidase activities. C. thermophilus CT2 produced cellobiohydrolase available at 50 degrees C, when grown on ferment liquid substrate, containing 1% Avicel, 0.14% (NH4 )2SO4, 0.2% KH2PO4, 0.03% CaC2 x 2H2O, 0.03% MnSO4 x 7H2O, 0.1% peptone, 0.05% yeast extract, 0.1% Tween 80 and trace element solution at 1mL/L, containing 18mmol/L FeSO4 x 7H2O, 6.6mmol/L MnSO4, 4.8mmol/L ZnSO4 x 7H2O and 15mmol/L COCl2. A cellobiohydrolase was purified to homogeneity by an inexpensive and straightforward method for extraction of the enzyme involving fractional ammonium sulphate precipitation, ion-exchange chromatography on DEAE-Sepharose Fast Flow, gel filtration on Sephacryl S-100 and ion-exchange chromatography on Q Sepharose Fast Flow. The molecular weight of the enzyme was estimated to be 66.3kDa by 12.5% SDS-PAGE and was to be 67.1kDa by gel filtration on Sephacryl S-100 respectively. Kinetic studies of the purified cellobiohydrolase of C. thermophilus CT2 showed that the Km for p-NPC (p-trophenylbeta-d-cellobioside) was 0.956mmol/L as determined from a Lineweaver-Bark plot. Optimum enzyme activity was at 65 degrees C and pH5.0. It was thermostable at 60 degrees C and remained 20% activity after 20min at 80 degrees C. The half life time of the enzyme at 70 degrees C was 1h. It indicated that the cellobiohydrolase possessed of excellent acid stability and thermostable property. The properties of the cellobiohydrolase make it possible to be good material in scientific researches of protein thermostable mechanism and good model for designing and constructing a new type protein in industry. The enzyme may also provide instructive insight on the diversity and mechanism of cellulose degradation by C. thermophilus CT2. As a thermophilic fungus C. thermophilus CT2 is an attractive potential source of cellulases. It indicates that C. thermophilus CT2 may be a new excellent industrialized fungus for producing cellulases through molecule biology means.
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PMID:[Purification and characterization of a cellobiohydrolase from the thermophilic fungus Chaetomium thermophilus CT2]. 1657 83

A facultatively anaerobic bacterium, Paenibacillus curdlanolyticus B-6, isolated from an anaerobic digester produces an extracellular xylanolytic-cellulolytic enzyme system containing xylanase, beta-xylosidase, arabinofuranosidase, acetyl esterase, mannanase, carboxymethyl cellulase (CMCase), avicelase, cellobiohydrolase, beta-glucosidase, amylase, and chitinase when grown on xylan under aerobic conditions. During growth on xylan, the bacterial cells were found to adhere to xylan from the early exponential growth phase to the late stationary growth phase. Scanning electron microscopic analysis revealed the adhesion of cells to xylan. The crude enzyme preparation was found to be capable of binding to insoluble xylan and Avicel. The xylanolytic-cellulolytic enzyme system efficiently hydrolyzed insoluble xylan, Avicel, and corn hulls to soluble sugars that were exclusively xylose and glucose. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of a crude enzyme preparation exhibited at least 17 proteins, and zymograms revealed multiple xylanases and cellulases containing 12 xylanases and 9 CMCases. The cellulose-binding proteins, which are mainly in a multienzyme complex, were isolated from the crude enzyme preparation by affinity purification on cellulose. This showed nine proteins by SDS-PAGE and eight xylanases and six CMCases on zymograms. Sephacryl S-300 gel filtration showed that the cellulose-binding proteins consisted of two multienzyme complexes with molecular masses of 1,450 and 400 kDa. The results indicated that the xylanolytic-cellulolytic enzyme system of this bacterium exists as multienzyme complexes.
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PMID:Paenibacillus curdlanolyticus strain B-6 xylanolytic-cellulolytic enzyme system that degrades insoluble polysaccharides. 1659 47

A third bgl operon containing bglE, bglF, bglI, and bglA was isolated from Pectobacterium carotovorum subsp. carotovorum LY34 (Pcc LY34). The sequences of BglE, BglF, and Bgll were similar to those of the phosphotransferase system (PTS) components IIB, IIC, and IIA respectively. BglF contains important residues for the phosphotransferase system. The amino acid sequence of BglA showed high similarity to various 6-phospho-beta-glucosidases and to a member of glycosyl hydrolase family 1. Sequence and structural analysis also revealed that these four genes were organized in a putative operon that differed from two operons previously isolated from Pcc LY34, bglTPB (accession no. AY542524) and ascGFB (accession no. AY622309). The transcription regulator for this operon was not found, and the EII complexes for PTS were encoded separately by three genes (bglE, bglF, and bglI). The BglA enzyme had a molecular weight estimated to be 57,350 Da by SDS-PAGE. The purified beta-glucosidase hydrolyzed salicin, arbutin, rhoNPG, rhoNPbetaG6P, and MUG, exhibited maximal activity at pH 7.0 and 40 degrees C, and displayed enhanced activity in the presence of Mg2+ and Ca2+. Two glutamate residues (Glu178 and Glu378) were found to be essential for enzyme activity.
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PMID:Cloning and comparison of third beta-glucoside utilization (bglEFIA) operon with two operons of Pectobacterium carotovorum subsp. carotovorum LY34. 1663 44

The metagenomic DNAs were extracted and purified from alkalescence environmental samples directly. On the basis of the metagenomic DNA, the alkaline soil 16S rDNA library composed of 5,562 positive clones was constructed. The phylogenic tree indicated that the bacteria from the alkaline soils were bio-diversity. The metagenomic DNA library named AL01 was constructed by inserting restriction fragments of the purified DNAs into plasmids pGEM-3Zf(+) vector. This library contained 23,650 positive clones and the average foreign DNA fragments were about 3.2 kb. The length of the library covered 75.68 Mb. The efficiency of the metagenomic library was approximately 6,000 clones from 1g dry soil samples. After screening AL01 DNA library with the screening tactics of enzymes, we confirmed that a positive clone, designated pGXAA2011, contained an alkaline protease gene AP01. Enzymatic analysis proved that its reaction optimum pH was 9.5 and the optimum temperature was 40 degrees C. Furthermore, a clone, designated pGXAG142 was screened from metagenomic DNA library, which expresses beta-glucosidase. DNA sequence indicated that the potential ORF of pGXAG142, which was named unglu01, there was no DNA or amino acids identity with the known beta-glucosidase genes in the Genbank. The integrated ORF was cloned into pETBlue-2 vector and was then transformed into Tuner(DE3)pLacI. The recombinant expression clone could express beta-glucosidase on the screening plate clearly and the analysis of SDS-PAGE indicated that the target protein was about 29 kDa.
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PMID:[Cloning and diversity analysis of microorganism genes from alkalescence soil]. 1703 89

Disaccharidases (maltase, cellobiase, lactase, and sucrase), alpha-amylase, and glucoamylase in the camel small intestine were investigated to integrate the enzymatic digestion profile in camel. High activities were detected for maltase and glucoamylase, followed by moderate levels of sucrase and alpha-amylase. Very low activity levels were detected for lactase and cellobiase. Camel intestinal maltase-glucoamylase (MG) was purified by DEAE-Sepharose and Sephacryl S-200 columns. The molecular weight of camel small intestinal MG4 and MG6 were estimated to be 140,000 and 180,000 using Sephacryl S-200. These values were confirmed by SDS-PAGE, where the two enzymes migrated as single subunits. This study encompassed characterization of MGs from camel intestine. The Km values of MG4 and MG6 were estimated to be 13.3 mM and 20 mM maltose, respectively. Substrate specificity for MG4 and MG6 indicated that the two enzymes are maltase-glucoamylases because they catalysed the hydrolysis of maltose and starch with alpha-1,4 and alpha-1,6 glycosidic bonds, but not sucrose with alpha-1,2 glycosidic bond which was hydrolyzed by sucrase-isomaltase. Camel intestinal MG4 and MG6 had the same optimum pH at 7.0 and temperature optimum at 50 degrees C and 40 degrees C, respectively. The two enzymes were stable up to 50 degrees C and 40 degrees C, followed by strong decrease in activity at 60 degrees C and 50 degrees C, respectively. The effect of divalent cations on the activity of camel intestinal MG4 and MG6 was studied. All the examined divalent cations Ca(2+), Mn(2+), Mg(2+), Co(2+) and Fe(3+) had slight effects on the two enzymes except Hg(2+) which had a strong inhibitory effect. The effect of different inhibitors on MG4 and MG6 indicated that the two enzymes had a cysteine residue.
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PMID:Disaccharidase activities in camel small intestine: biochemical investigations of maltase-glucoamylase activity. 1709 55

In certain maize genotypes, called "null," beta-glucosidase does not enter gels and therefore cannot be detected on zymograms after electrophoresis. Such genotypes were originally thought to be homozygous for a null allele at the glu1 gene and thus devoid of enzyme. We have shown that a beta-glucosidase-aggregating factor (BGAF) is responsible for the "null" phenotype. BGAF is a chimeric protein consisting of two distinct domains: the disease response or "dirigent" domain and the jacalin-related lectin (JRL) domain. First, it was not known whether the lectin domain in BGAF is functional. Second, it was not known which of the two BGAF domains is involved in beta-glucosidase binding and aggregation. To this end, we purified BGAF to homogeneity from a maize null inbred line called H95. The purified protein gave a single band on SDS-PAGE, and the native protein was a homodimer of 32-kDa monomers. Native and recombinant BGAF (produced in Escherichia coli) agglutinated rabbit erythrocytes, and various carbohydrates and glycoproteins inhibited their hemagglutination activity. Sugars did not have any effect on the binding of BGAF to the beta-glucosidase isozyme 1 (Glu1), and the BGAF-Glu1 complex could still bind lactosyl-agarose, indicating that the sugar-binding site of BGAF is distinct from the beta-glucosidase-binding site. Neither the dirigent nor the JRL domains alone (produced separately in E. coli) produced aggregates of Glu1 based on results from pull-down assays. However, gel shift and competitive binding assays indicated that the JRL domain binds beta-glucosidase without causing it to aggregate. These results with those from deletion mutagenesis and replacement of the JRL domain of a BGAF homolog from sorghum, which does not bind Glu1, with that from maize allowed us to conclude that the JRL domain of BGAF is responsible for its lectin and beta-glucosidase binding and aggregating activities.
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PMID:Maize beta-glucosidase-aggregating factor is a polyspecific jacalin-related chimeric lectin, and its lectin domain is responsible for beta-glucosidase aggregation. 1721 May 77

Flavone content and glucosidase activity were analyzed in various species of the genera Chamomilla, Matricaria, and Anthemis, especially during the development of the chamomile flower heads. The accumulation profile of flavonoids and the increase in enzyme activity were similar during ontogenesis. The accumulation of apigenin derivatives in closely related species was always linked to the occurrence of a catabolic beta-glucosidase in the respective plant organ. The flavone-glucoside-cleaving beta-glucosidase (FGG) from the ligulate florets of chamomile was purified to electrophoretic homogeneity by the following procedure: ammonium sulphate fractionation, anion exchange on Mono Q, hydrophobic interaction chromatography on Bio-Gel TSK Phenyl-5-PW, and gel filtration on Superose 12. The M (r) of the native enzyme was determined by gel filtration (500 kDa) and native PAGE (334 kDa). Only one subunit with an M (r) of 60 kDa could be detected after SDS-PAGE. The isoelectric point as determined by chromatofocussing on Mono P was at pH 4.6. During the purification procedure only one glucosidase activity appeared. A partially purified enzyme was used for characterization. The temperature optimum was at 37 degrees C and the pH-optimum 5.6. Energy of activation was 32.9 kJ/mol. The determination of the kinetic constants with various aryl glycosides proved a high affinity of the FGG towards flavone 7- O-glucosides. alpha-Glycosides and disaccharides were not hydrolyzed. Transglucosylation to an acceptor other than water was observed. Reagents interacting with sulfhydryl-groups strongly inhibited the enzyme.
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PMID:Purification and Characterization of a Flavone 7-O-Glucoside-Specific Glucosidase from Ligulate Florets of Chamomilla recutita. 1723 4

The purification and characterization of a novel extracellular beta-glucosidase from Paecilomyces thermophila J18 was studied. The beta-glucosidase was purified to 105-fold apparent homogeneity with a recovery yield of 21.7% by DEAE 52 and Sephacryl S-200 chromatographies. Its molecular masses were 116 and 197 kDa when detected by SDS-PAGE and gel filtration, respectively. It was a homodimeric glycoprotein with a carbohydrate content of 82.3%. The purified enzyme exhibited an optimal activity at 75 degrees C and pH 6.2. It was stable up to 65 degrees C and in the pH range of 5.0-8.5. The enzyme exhibited a broad substrate specificity and significantly hydrolyzed p-nitrophenyl-beta- d-glucopyranoside ( pNPG), cellobiose, gentiobiose, sophorose, amygdalin, salicin, daidzin, and genistin. Moreover, it displayed substantial activity on beta-glucans such as laminarin and lichenan, indicating that the enzyme has some exoglucanase activity. The rate of glucose released by the purified enzyme from cellooligosaccharides with a degree of polymerization (DP) ranging between 2 and 5 decreased with increasing chain length. Glucose and glucono-delta-lactone inhibited the beta-glucosidase competitively with Ki values of 73 and 0.49 mM, respectively. The beta-glucosidase hydrolyzed pNPG, cellobiose, gentiobiose, sophorose, salicin, and amygdalin, exhibiting apparent Km values of 0.26, 0.65, 0.77, 1.06, 1.39, and 1.45 mM, respectively. Besides, the enzyme showed transglycosylation activity, producing oligosaccharides with higher DP than the substrates when cellooligosaccharides were hydrolyzed. These properties make this beta-glucosidase useful for various biotechnological applications.
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PMID:Characterization of a thermostable extracellular beta-glucosidase with activities of exoglucanase and transglycosylation from Paecilomyces thermophila. 1809 50

An extracellular beta-glucosidase was purified 154-fold to electrophoretic homogeneity from the brown-rot basidiomycete Fomitopsis palustris grown on 2.0% microcrystalline cellulose. SDS-polyacrylamide gel electrophoresis gel gave a single protein band and the molecular mass of purified enzyme was estimated to be approximately 138 kDa. The amino acid sequences of the proteolytic fragments determined by nano-LC-MS/MS suggested that the protein has high homology with fungal beta-glucosidases that belong to glycosyl hydrolase family 3. The Kms for p-nitorophenyl-beta-D-glucoside (p-NPG) and cellobiose hydrolyses were 0.117 and 4.81 mM, and the Kcat values were 721 and 101.8 per sec, respectively. The enzyme was competitively inhibited by both glucose (Ki= 0.35 mM) and gluconolactone (Ki= 0.008 mM), when p-NPG was used as substrate. The optimal activity of the purified beta-glucosidase was observed at pH 4.5 and 70 degrees. The F. palustris protein exhibited half-lives of 97 h at 55 degrees and 15 h at 65 degrees, indicating some degree of thermostability. The enzyme has high activity against p-NPG and cellobiose but has very little or no activity against p-nitrophenyl-beta-lactoside, p-nitrophenyl-beta-xyloside, p-nitrophenyl-alpha-arabinofuranoside, xylan, and carboxymethyl cellulose. Thus, our results revealed that the beta-glucosidase from F. palustris can be classified as an aryl-beta-glucosidase with cellobiase activity.
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PMID:Purification and characterization of thermostable beta-glucosidase from the brown-rot basidiomycete Fomitopsis palustris grown on microcrystalline cellulose. 1833 93


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