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)

We have previously identified and purified a novel beta-glucosidase, designated PNGH (pyridoxine-5'-beta-D-glucoside hydrolase), from the cytosolic fraction of pig intestinal mucosal. PNGH catalyses the hydrolysis of PNG (pyridoxine-5'-beta-D-glucoside), a plant derivative of vitamin B6 that exhibits partial nutritional bioavailability in humans and animals. Preliminary amino acid sequence analysis indicated regions of close similarity of PNGH to the precursor form of LPH (lactase-phlorizin hydrolase), the beta-glucosidase localized to the brush-border membrane. We report in the present study amino acid sequence data for PNGH and results of Northern blot analyses, upon which we propose a common genomic origin of PNGH and LPH. Internal Edman sequencing of the PNGH band isolated by SDS/PAGE yielded data for 16 peptides, averaging 10.8 amino acids in length. These peptides from PNGH (approx. 140 kDa) were highly similar to sequences existing over most of the length of the >200 kDa precursor of rabbit LPH; however, we found no PNGH sequences that corresponded to approx. 350 amino acids between positions 463 and 812 of the LPH precursor, a region encoded by exon 7 of the LPH precursor gene (amino acids 568-784), and no sequences that corresponded to regions near the N-terminus. MS analysis of tryptic peptides yielded 25 peptides, averaging 15 amino acids, with masses that matched segments of the rabbit LPH precursor. Northern blot analysis of pig and human small intestinal polyadenylated mRNA using a non-specific LPH cDNA probe showed an expected approx. 6 kb transcript of the LPH precursor, but also an approx. 4 kb transcript that was consistent with the size predicted from the PNGH protein mass. Using a probe specific to the region encoded by exon 7, hybridization occurred only with the 6 kb transcript. Based on these observations, we propose that both PNGH and LPH enzymes have the same genomic origin, but differ in transcriptional and, possibly, post-translational processing.
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PMID:Partial amino acid sequence and mRNA analysis of cytosolic pyridoxine-beta-D-glucoside hydrolase from porcine intestinal mucosa: proposed derivation from the lactase-phlorizin hydrolase gene. 1497 28

An isoflavone conjugates hydrolyzing beta-glucosidase (ICHG) from endophytic bacterium, Pseudomonas ZD-8 was purified to homogeneity by successive ammonium sulfate precipitation, gel filtration on SephadexG-100, DEAE-sephrose CL-6B and DEAE-Sephacel chromatography. The enzyme was a monomeric protein with an apparent molecular mass of 33 kDa as determined by SDS-PAGE and gel filtration. It was optimally active at pH 6.0 and 40 degrees C and had a specific activity of 1485 U mg of protein(-1) against genistin. The ICHG readily hydrolyzed rho-nitrophenyl-beta-glucoside, rho-nitrophenyl-beta-galactoside, genistin, daidzin, with Km values of 1.64, 1.87, 0.012, 0.014 mM, respectively. The ICHG showed a pronounced specificity for glucose in the 7-position of isoflavone and flavone conjugates and hydrolyzed effectively malonyl isoflavone glucosides as well as isoflavone glucosides with similar kinetics. Glucose and glucono-delta-lactone inhibited the enzyme competitively with Ki values of 84 mM and 23 mM, respectively. The enzyme did not require divalent cations for activity, and its activity was strongly inhibited by Hg2+, Ag+, rho-chloromercuribenzoate, iodoacetic acid, and N-ethylmaleimide while reducing agents such as beta-mercaptoethanol, dithiothreitol, dithioerythritol, glutathione slightly activated the enzyme.
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PMID:Purification and characterization of an isoflavone-conjugates-hydrolyzing beta-glucosidase from endophytic bacterium. 1505 33

Corn coleoptile lectin is present with beta-glucosidase (EC. 3.2.1.2.1) in a single tightly bound molecular association complex (88.7 kDa). SDS-PAGE of the molecular complex dissociates into two main components. Of these, at a concentration of 75%, the corn coleoptile beta-glucosidase (60 kDa) is identified by enzymatic activity, with two 16-amino acid tryptic peptides displaying close homology with the primary structure of the enzyme. In separate experiments, we isolated homogenous monomeric enzyme of corn coleoptile. This allowed us to conclude that lectin properties like erythrocyte agglutination, found in the (88.7 kDa) molecular complex, is not due to the beta-glucosidase bound in it. Another protein (30 kDa) dissociated from the same SDS-PAGE gels rendered several tryptic peptides, including a 20-amino acid sequence V(L)GP(Q)W(A)GGSGGSPVDITAEPQR closely homologous to the putative beta-glucosidase aggregating factor (BGAF) precursor described recently. Tryptic peptide SAFTE(A)WN(V)ELK(V) was also present in the BGAF precursor. KFHEQR peptide was not present in BGAF precursor or any other protein sequence examined. Tryptic peptide TYGPFGA showed good homology with the BGAF precursor protein, FEGLYLFHTPLGSGAN peptide displayed identity with the BGAF precursor sequence. Thus, the 30 kDa protein does not appear to be identical to BGAF, but is rather a similar molecule which could be endowed with the lectin properties of the 88.7 kDa molecular complex.
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PMID:Molecular association of lectin and beta-glucosidase in corn coleoptile. 1554 Dec 99

A putative bgl operon of Pectobacterium carotovorum subsp. carotovorum LY34 (Pcc LY34) was isolated. Sequence analysis of the 5,557 bp cloned DNA fragment (accession no. AY542524) showed three open reading frames (bglT, bglP, and bglB) predicted to encode 287, 633, and 468 amino acid proteins respectively. BglT and BglP ORFs show high similarity to that of the Pectobacterium chrysanthemi ArbG antiterminator and ArbF permease respectively. Also, the latter contains most residues important for phosphotransferase activity. The amino acid sequence of BglB showed high similarity to various beta-glucosidases and is a member of glycosyl hydrolase family 1. The purified BglB enzyme hydrolyzed salicin, arbutin, pNPG, and MUG. The molecular weight of the enzyme was estimated to be 53,000 Da by SDS-PAGE. The purified beta-glucosidase exhibited maximal activity at pH 7.0 and 40 degrees C, and its activity was enhanced in the presence of Mg(2+). Two glutamate residues (Glu(173) and Glu(362)) were found to be essential for enzyme activity.
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PMID:Analysis of bgl operon structure and characterization of beta-glucosidase from Pectobacterium carotovorum subsp. carotovorum LY34. 1556 64

The present study analyzed the existence of carbohydrases in camel pancreas compared to some other ruminants. Disaccharidases (maltase, cellobiase, lactase, trehalase and sucrase), glucoamylase and alpha-amylase were detected in pancreas of camel, sheep, cow and buffalo. Enzyme levels in sheep were lower than in the other ruminants. The highest level was detected for alpha-amylase (EC 3.2.1.2). Moderate activity levels were detected for glucoamylase (EC 3.2.1.3) and maltase (EC 3.2.1.20), while other disaccharidases showed very low activity. The results suggested that, in addition to alpha-amylase, glucoamylase and maltase may be synthesized and secreted from pancreas to the small intestine in ruminants. Camel pancreatic glucoamylase was purified and characterized. The purification procedure included glycogen precipitation and chromatography on DEAE-Sepharose and Sepharose 6B. The molecular mass was 58 kDa for native and denatured enzyme using gel filtration and SDS-PAGE, respectively. The enzyme had a pH optimum at 5.5 and a Km of 10 mg starch/mL with more affinity toward potato soluble starch than the other carbohydrates. Glucoamylase had a temperature optimum at 50 degrees C with heat stability up to 30 degrees C. The effect of different cations and inhibitors was examined. The camel pancreatic glucoamylase may possess an essential thiol.
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PMID:Carbohydrases in camel (Camelus dromedarius) pancreas. Purification and characterization of glucoamylase. 1562 12

An asc operon of Pectobacterium carotovorum subsp. carotovorum LY34 (Pcc LY34) was isolated from a genomic library in a screen for beta-glucosidase activities. Sequence analysis of the 5618-bp cloned DNA fragment (accession number AY622309) showed three open reading frames (ascG, ascF, and ascB) that are predicted to encode 375, 486, and 476 amino acid proteins, respectively. The AscG ORF shared a high similarity with the Escherichia coli AscG repressor. The AscF ORF shared 81% identity with the E. coli AscF PTS enzyme II(asc), while the AscB ORF was highly similar to 6-phospho-beta-glucosidases and is a member of the glycosyl hydrolase family 1. The purified AscB enzyme hydrolyzed salicin, arbutin, pNPG, and MUG. It exhibited maximal activity at pH 7.0 and 40 degrees C, and its activity was enhanced in the presence of Mg(2+) and Ca(2+). The molecular weight of the enzyme was estimated to be 53 000 Da by SDS-PAGE. Two conserved glutamate residues (Glu(182) and Glu(374)) were shown to be important for AscB activity.
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PMID:Structural and biochemical analysis of the asc operon encoding 6-phospho-beta-glucosidase in Pectobacterium carotovorum subsp. carotovorum LY34. 1574 78

beta-Glucosidases are important in the formation of floral tea aroma and the development of resistance to pathogens and herbivores in tea plants. A novel beta-glucosidase was purified 117-fold to homogeneity, with a yield of 1.26%, from tea leaves by chilled acetone and ammonium sulfate precipitation, ion exchange chromatography (CM-Sephadex C-50) and fast protein liquid chromatography (FPLC; Superdex 75, Resource S). The enzyme was a monomeric protein with specific activity of 2.57 U/mg. The molecular mass of the enzyme was estimated to be about 41 kDa and 34 kDa by SDS-PAGE and FPLC gel filtration on Superdex 200, respectively. The enzyme showed optimum activity at 50 deg;C and was stable at temperatures lower than 40 degrees C. It was active between pH 4.0 and pH 7.0, with an optimum activity at pH 5.5, and was fairly stable from pH 4.5 to pH 8.0. The enzyme showed maximum activity towards pNPG, low activity towards pNP-Galacto, and no activity towards pNP-Xylo.
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PMID:Purification and partial characterization of beta-glucosidase from fresh leaves of tea plants (Camellia sinensis (L.) O. Kuntze). 1594 50

Genomic DNA fragment encoding a novel beta-glucosidase-like activity of the yeast Pichia etchellsii was cloned and expressed in Escherichia coli. An open-reading frame of 1515bp, termed mugA, coding for a protein of predicted molecular mass of approximately 54kDa was confirmed for this activity. The sequence of the deduced protein did not show homology with the generic beta-glucosidases but a high degree of identity was seen with several Ser-Asp (SD)-rich cell-surface-associated proteins. The secondary structure prediction program 3D-PSSM indicated the protein to be composed of largely helical and coiled structures, which was confirmed by circular dichroism spectroscopy. The encoded protein, MUGA, was purified by about 53-fold and characterized as a monomer of 52.1kDa by SDS-PAGE and MALDI-TOF. The protein displayed high hydrolytic activity on methylumbelliferyl beta-d-glucoside but relatively very little hydrolysis of p-nitrophenyl beta-d-glucoside and gentiobiose, characteristic substrates for beta-glucosidases. The binding experiments performed between P. etchellsii cells and the purified E. coli expressed MUGA indicated binding with the cell surface, which was monitored by fluorescence microscopy. In competition experiments with the SD dipeptide, less protein was shown to bind to the cell surface, in a concentration-dependent manner.
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PMID:Cloning, sequence analysis, and characterization of a novel beta-glucosidase-like activity from Pichia etchellsii. 1613 62

For the first time, a beta-glucosidase gene from the edible straw mushroom, Volvariella volvacea V1-1, has been over-expressed in E. coli. The gene product was purified by chromatography showing a single band on SDS-PAGE. The recombinant enzyme had a molecular mass of 380 kDa with subunits of 97 kDa. The maximum activity was at pH 6.4 and 50 degrees C over a 5 min assay. The purified enzyme was stable from pH 5.6-8.0, had a half life of 1 h at 45 degrees C. The beta-glucosidase had a K(m) of 0.2 mM: for p-nitrophenyl-beta-D: -glucopyranoside.
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PMID:Expression, purification and characterization of a recombinant beta-glucosidase from Volvariella Volvacea. 1621 51

The subunit composition of the extracellular complex from Clostridium thermocellum was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Twenty-six bands, representing proteins with apparent molecular sizes ranging from 37,500 to 185,000 Da, could be detected by silver staining. Cultivation of the bacteria with the substrate Avicel, Sigma cellulose, Solka floc, or cellobiose as the carbon source had no influence on the number of detectable protein bands. By activity staining with the substrate carboxymethyl cellulose or xylan added to the SDS-polyacrylamide gels, 15 of the 26 bands exhibited endoglucanase activity and 13 showed xylanase activity. In 8 of the 26 bands, both activities could be found. As minor activities, beta-glucosidase, beta-xylosidase, beta-galactosidase, and beta-mannosidase activities could be demonstrated in the cellulase complex. Upon measuring the release of para-nitrophenol (PNP) from PNP-cellobioside and determining the amount of glucose formed, the presence of exoglucanase activity was indicated. Upon glycoprotein staining of SDS-polyacrylamide gels, 14 of the 26 bands reacted positive, indicating the glycoprotein nature of the respective proteins. Four proteins (apparent molecular sizes, 58,000, 72,500, 94,000, and 110,000 Da) could be enriched from the originally bound cellulase complex by preparative SDS-PAGE. The two smaller proteins exhibited xylanase activity, whereas the 94,000-Da protein had endo- and exoglucanase activity, and the 110,000-Da protein degraded PNP-pyranosides.
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PMID:Subunit Composition and Glycosidic Activities of the Cellulase Complex from Clostridium thermocellum JW20. 1634 80


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