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:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The common identity of human acidic beta-D-glucosidase (beta-D-glucoside glucohydrolase, EC 3.2.1.21) and beta-D-xylosidase (1,4-beta-D-xylan xylohydrolase, EC 3.2.1.37) as one enzyme and that of acidic beta-D-galactosidase (beta-D-galactoside galactohydrolase, EC 3.2.1.23), beta-D-fucosidase (no allotted EC number) and alpha-L-arabinosidase (alpha-L-arabinofuranoside arabinohydrolase, EC 3.2.1.55) as another enzyme is indicated by similar binding patterns of glycosidase activities of each enzyme to various lectins. by similar ratios between their intra- and extracellular levels in normal and I-cell fibroblasts and by their deficiencies in liver tissues from patients with Gaucher disease and GM1 gangliosidosis, respectively. A third enzyme, neutral beta-D-galactosidase, purified to homogeneity from human liver has been shown to possess all these five glycosidase activities at neutral pH. These neutral enzymic activities were not bound by any of the lectins examined and found to be reduced in liver and spleen of a patient with neutral beta-D-galactosidase deficiency. An additional form of beta-D-xylosidase with optimal activity at pH 7.4 was bound by the fucose-binding lectin from Ulex eurpaeus while no binding was observed for the acidic (pH 4.8) and neutral (pH 7.0) beta-D-xylosidase activities of the multiple glycosidase enzymes.
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PMID:Multiple carbohydrate-cleaving specificities in human acidic and neutral glycosidases. 11 23

Homogenates of Giardia lamblia trophozoites exhibited the following hydrolase activities: acid phosphatase (EC 3.1.3.2), proteinase (EC 3.1.4) with urea-denatured hemoglobin and N-benzoyl-DL-arginine-2-naphthylamide as substrates, deoxyribonuclease (EC 3.1.4.5), and ribonuclease (EC 2.7.7.16). beta-N-Acetylglucosaminidase (EC 3.2.1.30), beta-galactosidase (EC 3.2.1.23), beta-glucuronidase (EC 3.2.1.31), alpha-D-glucosidase (EC 3.2.1.20), beta-D-glucosidase (EC 3.2.1.21), and beta-D-xylosidase (EC 3.2.1.37) activities were below the level of detection. Differential and isopycnic centrifugation of homogenates demonstrated that giardial hydrolases were localized in a single-particle population sedimenting at 7200g for 30 min. The particles had a buoyant density in sucrose of 1.15 and exhibited latency. Latency was completely destroyed by Triton X-100 or 15 cycles of freezing and thawing. After centrifugation of Triton- or freeze-thaw-treated particle fractions, the hydrolase activities, though no longer latent, were still sedimentable suggesting tight binding to the organelle membrane. Latency was destroyed simultaneously for all hydrolases, in direct proportion to the amount of Triton added to a particle preparation or to the number of times a particle preparation was subjected to freezing and thawing. These results support the suggestion that the hydrolases of G. lamblia trophozoites are localized in a single-particle population of lysosome-like organelles.
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PMID:Giardia lamblia: localization of hydrolase activities in lysosome-like organelles of trophozoites. 327 50

An electrophoretic system using cellulose acetate has been developed for the resolution of beta-glucosidase isozymes (beta-D-glucoside glucohydrolase, EC 3.2.1.21 and D-glucosyl-N-acylsphingosine glucohydrolase, EC 3.2.1.45) in human tissue homogenates. Electrophoresis of homogenates from normal and Type 1 Gaucher disease tissues revealed two fluorescent bands of beta-glucosidase activity which corresponded to the acid and neutral isozymes separated by concanavalin A-Sepharose chromatography. The acid isozyme has only beta-glucosidase activity, whereas the neutral isozyme also exhibited alpha-L-arabinosidase (alpha-L-arabinofuranoside arabinofuranohydrolase, EC 3.2.1.55), beta-D-galactosidase (beta-D-galactoside galactohydrolase, EC 3.2.1.23) and beta-D-xylosidase (1,4-beta-D-xylan xylohydrolase, EC 3.2.1.37) activities, using the appropriate 4-methylumbelliferyl glycoside. In homogenates of cultured skin fibroblasts, only the acid isozyme was observed which co-electrophoresed with the acidic activity in other tissue homogenates. The acidic activity in tissue and fibroblast homogenates from Type 1 Gaucher disease appeared to co-electrophorese with the acid isozyme in normal tissues, but had markedly reduced activity.
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PMID:Electrophoretic separation of neutral and acid beta-glucosidase isozymes in human tissues. 677 81

The xyloglucan from cotyledons of Hymenaea courbaril was hydrolysed with endo-(1,4)-beta-D-glucanase (cellulase) and analysed by TLC and HPAEC. The limit digest was different from those obtained from xyloglucans of Tamarindus indica and Copaifera langsdorffii. On treatment with nasturtium beta-galactosidase, two main oligosaccharides were detected by TLC and HPAEC. Using a process of enzymatic sequencing involving alternate treatments with a pure xyloglucan oligosaccharide-specific alpha-xylosidase, and a pure beta-glucosidase, both from nasturtium, their structures were deduced to be XXXG and a new oligosaccharide XXXXG. These structures were confirmed by 1H NMR. The relative proportions of XXXG and XXXXG indicate that approximately half of the subunits in Hymenaea xyloglucan are based on the new oligosaccharides. In the native polymer the XXXXG subunits are likely to carry galactosyl substituents in varying proportions, since cellulase hydrolysates contained many bands which were converted to XXXXG on hydrolysis with nasturtium beta-galactosidase. Although no comparative studies on the physico-chemical properties of Hymenaea courbaril xyloglucan have yet been performed, our results indicate that this polymer is less interactive with iodine when compared with T. indica and C. langsdorffii xyloglucans, suggesting that changes in conformation may occur due to the presence of XXXXG.
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PMID:A new family of oligosaccharides from the xyloglucan of Hymenaea courbaril L. (Leguminosae) cotyledons. 935 37

A beta-D-glucosidase has been purified to apparent homogeneity from the cotyledons of germinated nasturtium (Tropaeolum majus L.) seedlings during the mobilization of the xyloglucan stored in the cotyledonary cell walls. The purified protein (Mr 76, 000; a glycoprotein; pl > 9.5; apparent pH optimum 4.5; temperature optimum 30 degrees C) catalysed the hydrolysis of p-nitrophenyl-beta-D-glucopyranoside, cello-oligosaccharides, beta-linked glucose disaccharides, and certain xyloglucan oligosaccharides. Glucose disaccharides with different linkages were hydrolysed at different rates [(1-->3) > (1-->4) > (1-->2) > (1-->6)] with significant transglycosylation occurring in the early stages of the reaction. Cello-oligosaccharide hydrolysis was also accompanied by extensive transglycosylation to give transitory accumulations of higher oligosaccharides. At least some of the glycosyl linkages formed during transglycosylation were (1-->6)-beta. Xyloglucan oligosaccharides xylose-substituted at the non-reducing terminal glucose residue (XXXG, XXLG, XLXG and XLLG, where G is an unsubstituted glucose residue, X is a xylose-substituted glucose residue, and L is a galactosylxylose-substituted glucose residue) were not hydrolysed. Some xyloglucan oligosaccharides with an unsubstituted non-reducing terminal glucose residue (GXXG, GXLG and GXG) were hydrolysed, but others (GLXG and GLLG) were not. This indicated steric hindrance by L but not X substitution at the glucose residue next to the one at the non-reducing end of the oligosaccharide. Hydrolysis of xyloglucan oligosaccharides was not accompanied by transglycosylation. Natural xyloglucan subunit oligosaccharides (XXXG, XXLG, XLXG, XLLG) were totally degraded to their monosaccharide components when treated with nasturtium beta-D-galactosidase. (Edwards et al (1988) J. Biol. Chem. 263, 4333-4337), followed by alternations of nasturtium xyloglucan-specific alpha-xylosidase (Fanutti et al (1991) Planta 184, 137-147) and this enzyme. Several extensively overlapping cDNA clones were obtained by RT-PCR and by screening cDNA libraries. A composite, full-length DNA had an open reading frame of 1962 bp, encoding a polypeptide of 654 amino acids, including all N-terminal and internal sequences obtained from the purified beta-glucosidase protein, and a motif resembling plant signal sequences thought to direct proteins to the cell wall. Database searches revealed homology with beta-glucosidases from several sources (plant, bacteria, yeast), notably with glycosylhydrolases of 'Family 3', according to the classification of Henrissat (Henrissat (1991) Biochem. J. 280, 309-316). There was strong sequence homology with a beta-glucan exo-hydrolase from barley (Hrmova et al. (1996) J. Biol. Chem. 271, 5277-5286). The nasturtium beta-glucosidase is ascribed a role in xyloglucan mobilization, and its interaction with the alpha-xylosidase and the beta-galactosidase is modelled.
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PMID:A xyloglucan oligosaccharide-active, transglycosylating beta-D-glucosidase from the cotyledons of nasturtium (Tropaeolum majus L) seedlings--purification, properties and characterization of a cDNA clone. 974 92

Many seeds contain storage compounds that are used by the embryo/plantlet as a source of nutrients after germination. In seeds of Hymenaea courbaril, a leguminous tree, the main reserve consists of a structurally unusual xyloglucan stored in thickened walls of the cotyledon cells. The present work aimed to study H. courbaril xyloglucan metabolism during and after germination in order to compare its degrading system with the other known xyloglucan containing seeds. Polysaccharide degradation occurred after germination between 35 and 55 days after planting. The activities of alpha-xylosidase, beta-glucosidase, beta-galactosidase and XET rose during the period of xyloglucan disassembling but a low level of endo-beta-glucanase activity was detected, suggesting that this XET has high affinity for the oligosaccharides. The pH optimum of beta-galactosidase was different from the alpha-xylosidase, beta-glucosidase and XET optima suggesting that the former may be important in the control of the mobilisation process. A tentative model for xyloglucan disassembling in vivo is proposed, where beta-galactosidase allows the free oligosaccharides to bypass a transglycosylation cycle and be disassembled by the other exo-enzymes. Some ecophysiological comparisons among H. courbaril and other xyloglucan storing seeds are discussed.
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PMID:Xyloglucan mobilisation in cotyledons of developing plantlets of Hymenaea courbaril L. (Leguminosae-Caesalpinoideae). 1072 10

A facultatively anaerobic bacterium, designated strain COOI3B(T) (= ATCC BAA 136T = DSM 13966T), was isolated from the waters emitted by a bore well tapping the deep subterranean thermal waters of the Great Artesian Basin of Australia. The cells were straight to slightly curved rods (0.5-0.8 x 2-25 microm) that occurred singly and rarely in pairs or in chains. Strain COOI3B(T) was motile by peritrichous flagella. It stained gram-negative, but electron micrographs showed a gram-positive-type cell wall. Spores were never observed and cells were heat-sensitive. Yeast extract at 0.02% (w/v) was required for growth and could also be used as a sole carbon and energy source at concentrations higher than 0.1% (w/v). The strain utilized amorphous iron(III), manganese(IV), nitrate, nitrite and fumarate as electron acceptors in the presence of yeast extract, glucose, sucrose, fructose, maltose, xylose, starch, glycerol, ethanol or lactate. Electron acceptors were not obligately required and growth was better in the presence of nitrate than in its absence. Acid was not produced from growth on carbohydrates. Tryptophan deaminase, H2S, arginine dihydrolase, lysine decarboxylase, beta-galactosidase, arabinosidase, glucuronidase, glucosaminidase, nitroanilidase, xylosidase and ornithine decarboxylase were not produced. Starch and gelatin, but not casein, were hydrolysed. Aesculin and catalase, but not oxidase and urease, were produced. Strain COOI3B(T) grew optimally at temperatures between 37 and 40 degrees C (the temperature growth range was 25-45 degrees C) and at pH 7.0-9.0 (the pH growth range was 6.0 to 9.5) with 5% (w/v) NaCl (the NaCl concentration growth range was 0.9%, w/v). The DNA base composition was 43 +/- 1 mol % G+C. Phylogenetic analysis indicated that it was a member of the family Bacillaceae, Bacillus infernus and Bacillus firmus being the closest phylogenetic neighbours (having a mean similarity value of 96%); hence, strain COOI3B(T) is designated as a novel species, Bacillus subterraneus sp. nov.
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PMID:Bacillus subterraneus sp. nov., an iron- and manganese-reducing bacterium from a deep subsurface Australian thermal aquifer. 1205 51

Protein engineers have widely adopted directed evolution as a design algorithm, but practitioners have not come to a consensus about the best method to evolve protein molecular recognition. We previously used DNA shuffling to direct the evolution of Escherichia coli beta-glucuronidase (GUS) variants with increased beta-galactosidase activity. Epistatic (synergistic) mutations in amino acids 557, 566, and 568, which are part of an active site loop, were identified in that experiment (Matsumura, I., and Ellington, A. D. (2001) J. Mol. Biol. 305, 331-339). Here we show that site saturation mutagenesis of these residues, overexpression of the resulting library in E. coli, and high throughput screening led to the rapid evolution of clones exhibiting increased activity in reactions with p-nitrophenyl-beta-d-xylopyranoside (pNP-xyl). The xylosidase activities of the 14 fittest clones were 30-fold higher on average than that of the wild-type GUS. The 14 corresponding plasmids were pooled, amplified by long PCR, self-ligated with T4 DNA ligase, and transformed into E. coli. Thirteen clones exhibiting an average of 80-fold improvement in xylosidase activity were isolated in a second round of screening. One of the evolved proteins exhibited a approximately 200-fold improvement over the wild type in reactivity (k(cat)/K(m)) with pNP-xyl, with a 290,000-fold inversion of specificity. Sequence analysis of the 13 round 2 isolates suggested that all were products of intermolecular recombination events that occurred during whole plasmid PCR. Further rounds of evolution using DNA shuffling and staggered extension process (StEP) resulted in modest improvement. These results underscore the importance of epistatic interactions and demonstrate that they can be optimized through variations of the facile whole plasmid PCR technique.
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PMID:Rapid evolution of beta-glucuronidase specificity by saturation mutagenesis of an active site loop. 1506 62

All four glycanases necessary for the degradation of xyloglucan oligosaccharides (alpha-fucosidase, alpha-xylosidase, beta-galactosidase and beta-glucosidase) were found in the apoplastic fluid of Arabidopsis thaliana. These activities acted cooperatively on xyloglucan oligosaccharides (XLFG), leading to the sequential formation of XXFG, XXLG, XXXG, GXXG and XXG, as identified by matrix-assisted laser desorption ionization time of flight (MALDI-TOF). AtFXG1 (At1g67830) and AtXYL1 (At1g68560) had been previously identified as the Arabidopsis genes coding for alpha-fucosidase and alpha-xylosidase, respectively. As for the genes coding for beta-galactosidase activity, we identified in phylogenetic trees 12 candidates from family 35 of glycoside hydrolases. Similarly, four genes from family 3 were selected as possible beta-glucosidases active on xyloglucan. The expression level of all the selected genes was studied in different plant regions (young and mature rosette leaves, apical and basal region of the inflorescence stem, roots, flower and siliques) using quantitative real-time reverse transcription-PCR. The expression patterns were very diverse as well as their relationship with growth rates, showing a very complex situation. This could lead to highly varying proportions of the different xyloglucan oligosaccharides in different plant regions and developmental stages.
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PMID:Apoplastic glycosidases active against xyloglucan oligosaccharides of Arabidopsis thaliana. 1626 99

The anaerobic fungus Anaeromyces mucronatus KF8 grown in batch culture on M10 medium with rumen fluid and microcrystalline cellulose as carbon source produced a broad range of enzymes requisite for degradation of plant structural and storage saccharides including cellulase, endoglucanase, xylanase, alpha-xylosidase, beta-xylosidase, alpha-glucosidase, beta-glucosidase, beta-galactosidase, mannosidase, cellobiohydrolase, amylase, laminarinase, pectinase and pectate lyase. These enzymes were detected in both the intra- and extracellular fractions, but production into the medium was prevalent with the exception of intracellular beta-xylosidase, chitinases, N-acetylglucosaminidase, and lipase. Xylanase activity was predominant among the polysaccharide hydrolases. Extracellular production of xylanase was stimulated by the presence of cellobiose and oat spelt xylan. Zymogram of xylanases of strain KF8 grown on different carbon sources revealed several isoforms of xylanases with approximate molar masses ranging from 26 to 130 kDa.
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PMID:Xylanases of anaerobic fungus Anaeromyces mucronatus. 2068 May 72


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