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)

beta-Glucosidase A from bitter almonds was inhibited by the substrate analogue 6-bromo-3,4,5-trihydroxycyclo[2-3H]hex-1-ene oxide. Incorporation of 2 mol inhibitor/mol of dimeric enzyme resulted in total loss of activity. From tryptic digests of the labeled enzyme two radioactive peptides were isolated and their sequence determined (binding site of inhibitor underlined): peptide I, containing approx. 60% of the label: Ile-Thr-Glx-Glx-Gly-Val--Phe-Gly-Asp-Ser-Glx-(Ala, Asx2, Pro)-Lys and peptide II with approx. 30% of the label: Gly-Thr-Glx-Asp. The specifity of the reaction of beta-glucosidases (beta-D-glucoside glucohydrolase, EC 3.2.1.21) with substrate-related epoxides indicates that the aspartic acid labeled in peptide I participates in the catalytic process of beta-glucoside hydrolysis. The labeling of a second site is interpreted in terms of two, mutually exclusive, binding modes of the inhibitor.
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PMID:Amino acid sequence at the active site of beta-glucosidase A from bitter almonds. 41 15

Modification of A. conoides beta-glucosidase by diethylpyrocarbonate caused rapid inactivation of the enzyme. The kinetic analyses showed that the inactivation by diethylpyrocarbonate resulted from the modification of an average of one histidine residue per mole of enzyme. The modified enzyme showed an increase in absorbance at 240 nm. Sulphydryl, lysine and tyrosine residues were not modified by diethylpyrocarbonate treatment. The substrate offered significant protection against diethylpyrocarbonates modification. The results indicate that diethylpyrocarbonate was interacting with the enzyme at or near the active site.
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PMID:Inactivation of a beta-glucosidase from Arthrobotrys conoides by diethyl pyrocarbonate: evidence of histidine at the active site. 152 73

A total of 32 strains of the family Leptospiraceae (23 strains of Leptospira interrogans, 6 strains of Leptospira biflexa, 2 strains of Leptonema and 1 strain of Leptospira parva) were examined for enzyme activities using 89 substrates (API ZYM system). More than 90% of the strains belonging to the family Leptospiraceae possessed strong activities of beta-D-galactosidase, beta-D-glucosidase and 5 esterases (C5, C6, C8, C9 and C10). More than 90% of the strains belonging to the genus Leptospira, except L. parva, had strong activities of L-lysine arylamidase and alpha-L-glutamate arylamidase. L. biflexa strains, except serovar andamana, were different from the other strains examined in that they possessed glycyl-glycine arylamidase, glycyl-phenylalanine arylamidase and L-tryptophan arylamidase. L. biflexa strains, except andamana, L. parva and Leptonema strains possessed strong activities of glycine arylamidase and leucyl-glycine arylamidase. Two strains of the genus Leptonema were different from the strains belonging to the genus Leptospira in that they possessed strong activities of beta-D-lactosidase. L. parva lacked alpha-D-galactosidase which other strains belonging to the family Leptospiraceae possessed. Dendrogram analysis revealed that strains belonging to the family Leptospiraceae were divided into 4 groups. The first group consisted of all strains belonging to L. interrogans and serovar andamana of L. biflexa; the second group consisted of the remaining 5 serovars of L. biflexa; the third group consisted of the genus Leptonema; and the fourth group consisted of only L. parva.
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PMID:Enzyme activities of the strains belonging to family Leptospiraceae detected by the API ZYM system. 289 26

An enzymatic characterization of 16 strains of Aeromonas species including A. hydrophila (7), A. sobria (5), and A. caviae (4) was carried out using API Peptidase (strips numbered 1, 2, 3, 4, 5, and 6); API Esterase and API "Osidase" test strips. A total of 89 substrates was used in the assay and included 59 arylamides (aminopeptides), 10 esters, and 20 carbohydrates. All three species were remarkably uniform in their reactivities. Nineteen (32%) of the arylamide substrates used were hydrolyzed by all three species. Very strong arylamidase activity was displayed by all three species for L-lysine, L-hydroxyproline, L-arginine, L-alanine, L-proline, and L-leucyl-L-alanine. Esterase activity was strongest against caproate (C6), caprylate (C8), nonanoate (C9), and caprate (C10) substrates. Only a limited number of carbohydrate substrates were hydrolyzed; strong N-acetyl-beta-D-glucosaminidase activity was given by all strains. Both A. hydrophila and A. caviae gave strong beta-D-glucosidase reactivities, while A. sobria appeared to be negative for this enzyme. The results of our preliminary study show that some of the enzymes examined may be useful in the identification and differentiation of these species. The API enzyme assays yielded rapid (4 hr) results. The assays were easy to perform, relatively inexpensive and reproducible. The importance of replicate testing and the inclusion of uninoculated (buffer only) controls as part of the assay is emphasized.
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PMID:Enzymatic characterization of three aeromonas species using API Peptidase, API "Osidase," and API Esterase test kits. 307 50

Extracts of Acanthamoeba castellanii (Neff) contain alpha- and beta-glucosidase, beta-galactosidase, beta-N-acetylglucosaminidase, amylase, and peptidase. All of these activities are optimal between pH 3 and 4. These extracts also were found to clarify suspensions of cell walls from nine different gram-positive bacteria, including Micrococcus lysodeikticus. The pH optimum for the lytic activity was between 3 and 4. The extent of lysis of the various cell walls did not correlate with the release of free amino groups and of free N-acetylated sugars from the walls during digestion with these extracts. Suspensions of cell walls of Escherichia coli (a gram-negative bacterium), Cordiceps militaris (a fungus), and Acanthamoeba cysts, as well as of colloidal chitin, were not clarified by incubation with these extracts, although reducing sugars were released from each of these materials. Exhaustive digestion of M. lysodeikticus walls by lysozyme released no free N-acetylglucosamine. The products of exhaustive digestion of this cell wall with Acanthamoeba extracts were free N-acetylglucosamine, free N-acetylmuramic acid, glycine, alanine, glutamic acid, lysine, and N-acetylmuramic acid peptide fragments. These results suggest that the amoeba extracts contain endo- and exo-hexosaminidases, in addition to beta-hexosaminidase and peptide hydrolases.
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PMID:Effect of lytic enzymes of Acanthamoeba castellanii on bacterial cell walls. 578 74

The basis for the lethal activity of a bacteriocin produced by Streptococcus mutans C3603 (serotype c) was studied. Bacteriocin C3603 was found to adsorb to cells of representative strains of the seven serotypes of S. mutans. S. mutans BHT (serotype b) was used to study the adsorption and the lethal properties of bacteriocin C3603. The adsorption of bacteriocin to cells of S. mutans BHT was inhibited by treatment of cells with protease and beta-glucosidase and by such ligands as poly-L-lysine, poly-L-arginine, L-aspartic acid, L-glutamic acid, glutathione, oxidized glutathione, poly-L-aspartic acid, and poly-L-glutamic acid. The adsorption to cells was also inhibited by oligosaccharides and glucosamine. Mixtures of anionic and cationic amino acids or polyamino acids did not greatly enhance or antagonize the inhibition of adsorption of bacteriocin C3603 to cells. Sodium hydroxide extracts of cell walls and cell wall-membranes contained carbohydrates and proteins; however, only proteins were found to bind to bacteriocin or to a bacteriocin affinity column. The sodium hydroxide extracts contained about 35 protein bands as determined by sodium dodecyl sulfate-polyacrylamide disc gel electrophoresis. Bacteriocin C3603 was found to immediately inhibit the synthesis of proteins, DNA, and RNA of cells and to slowly release DNA from cells of S. mutans BHT.
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PMID:Mode of inhibitory action of a bacteriocin produced by Streptococcus mutans C3603. 671 39

Members of the Streptococcus sanguis group (SSG) and Streptococcus milleri group (SMG) were screened for their ability to produce glycosidase, arylamidase (peptidase), protease, dextranase and glycosyltransferase activities. Species within each group produced unique patterns of activity. The most commonly produced glycosidases were beta-D-glucosidase, beta-D-galactosidase, N-acetyl-beta-D-glucosaminidase and N-acetyl-beta-D-galactosaminidase and the least commonly produced glycosidase activity was beta-fucosidase with Streptococcus intermedius (SMG) being the only species capable of producing the activity. For arylamidase activity, the most commonly produced type was lysine-arylamidase. Glycosidase and arylamidase activities were localized to particular sub-cellular fractions. alpha-galactosidase was found only in culture supernatant fluids whereas N-acetyl-beta-D-glucosaminidase was found in all fractions; the culture supernatant, cell wall, cell membrane and cytoplasm. No arylamidase activity was seen in culture supernatants. Phe-arg-arylamidase was found only in cytoplasmic fractions whereas val-pro-argarylamidase was found in cell walls, cell membranes and cytoplasmic fraction. Protease activity was measured as the degradation of bovine serum albumin (BSA) and casein. Casein was degraded by a number of strains whereas no species/strains were able to degrade BSA. Streptococcus intermedius, Streptococcus constellatus (SMG), Streptococcus mitior and Streptococcus defectivus (SSG) were the only species that produced hyaluronidase and no species produced chondroitin sulphatase. The groups were also examined for their abilities to produce glycosyltransferase and dextranase. Strep. sanguis, Streptococcus gordonii, Streptococcus mitis and Streptococcus oralis produced glucosyltransferase and, with the exception of the latter species, fructosyltransferase. No species within the SMG was capable of producing either glycosyltransferase.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Degradative enzymes of oral streptococci. 778 31

The gene coding for the beta-glycosidase from the archaeon Sulfolobus solfataricus has been overexpressed in Escherichia coli. The enzyme was purified to homogeneity with a rapid purification procedure employing a thermal precipitation as a crucial step. The final yield was 64% and the purification from the thermal precipitation was 5.4-fold. The expressed enzyme shows the same molecular mass, thermophilicity, thermal stability, and broad substrate specificity, with noticeable exocellobiase (glucan 1,4-beta-D-glucosidase) activity, of the enzyme purified from S. Solfataricus. We provide evidence that the beta-glycosidase can assume its functional state in E. coli without the contribution of N-epsilon-methylated lysine residues.
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PMID:Expression and extensive characterization of a beta-glycosidase from the extreme thermoacidophilic archaeon Sulfolobus solfataricus in Escherichia coli: authenticity of the recombinant enzyme. 854 Oct 22

Mutations enhancing the thermostability of beta-glucosidase A of Bacillus polymyxa, a family 1 glycosyl hydrolase, have been obtained after hydroxylamine mutagenesis of a plasmid containing the bglA gene, transformation of Escherichia coli with the mutagenized plasmid, and identification of transformant colonies that showed beta-glucosidase activity after a thermal treatment that inactivated the wild-type enzyme. Two additive mutations have been characterized that cause replacement of glutamate at position 96 by lysine and of methionine at position 416 by isoleucine respectively. The thermoresistant mutant enzymes showed increased resistance to other denaturing agents, such as pH and urea, while their kinetic parameters did not change. CD spectra indicated that the E96K replacement caused an increase in alpha-helix content. The observed effect of the M416I mutation is consistent with the lower content of cysteine and methionine found in family 1 enzymes of thermophilic species compared with similar ones from mesophilic organisms.
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PMID:Amino acid substitutions enhancing thermostability of Bacillus polymyxa beta-glucosidase A. 861 77

The production of the extracellular cellulolytic enzyme system (endoglucanase, exoglucanase and cellobiase) of N. catalinensis was tested with different nitrogen sources, inorganic and organic ones, in liquid culture medium with microcrystalline cellulose. The nitrogen compounds used were: potassium nitrate, sodium nitrate, ammonium nitrate, ammonium phosphate, ammonium sulphate, ammonium chloride, ammonium carbonate, ammonium acetate, ammonium tartrate, urea, casamino acids, glycine, L-alanine, L-leucine, L-proline, L-lysine, L-aspartic acid, L-glutamic acid, L-asparagine, L-glutamine, L-phenylalanine, L-tyrosine, L-tryptophan, L-methionine and L-cysteine. Among these, ammonium nitrate and ammonium tartrate gave the highest yields of cellulases in 20-day-old cultures at a concentration equivalent to 0.75 g N/l in both cases. Optimal temperature for cellulase production, growth and cellulose degradation was 23 degrees C. On the other hand, an initial pH of 6.5 gave the highest yields of endoglucanase and cellobiase. In the same way, at pH 6.5, maximal growth and cellulose degradation were achieved. However, maximal exoglucanase production and glycogen content were reached at pH 7.5.
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PMID:Influence of different cultural conditions on cellulase production by Nectria catalinensis. 962 4


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