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)

As a first step in the development of a reporter system for gene expression in halophilic archaea, a beta-galactosidase was purified 140-fold from Haloferax alicantei (previously phenon K, strain Aa2.2). An overproducing mutant was first isolated by UV mutagenesis and screening on agar plates containing X-Gal substrate. Cytoplasmic extracts of the mutant contained 25-fold higher enzyme levels than the parent. Purification of the active enzyme was greatly facilitated by the ability of sorbitol to stabilise enzyme activity in the absence of salt, which allowed conventional purification methods (e.g., ion-exchange chromatography) to be utilised. The enzyme was optimally active at 4 M NaCl and was estimated to be 180 +/- 20 kDa in size, consisting of two monomers (each 78 +/- 3 kDa). It cleaves several different beta-galactoside substrates such as ONP-Gal, X-Gal and lactulose, but not lactose, and also has beta-D-fucosidase activity. No beta-glucosidase, beta-arabinosidase or beta-xylosidase activity could be detected. The amino-acid sequence at the N-terminus and of four proteolytic products has been determined.
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PMID:Purification and analysis of an extremely halophilic beta-galactosidase from Haloferax alicantei. 904 5

The beta-D-glucosidase (EC. 3.2.1.21) activity of Bifidobacterium breve 203 was increased by acclimation with cellobiose, and the enzyme was purified to homogeneity from cell-free extracts of an acclimatized strain of B. breve clb, by ammonium sulfate fractionation and column chromatographies of anion-exchange, gel filtration, Gigapaite, and hydrophobic interaction. This enzyme had not only beta-D-glucosidase activity but also beta-D-fucosidase activity, which is specific to Bifidobacteria in intestinal flora. The molecular weight of the purified enzyme was estimated to be 47,000-48,000 and the enzyme was assumed to be a monomeric protein. The optimum pH and temperature of the enzyme were around 5.5 and 45 degrees C, respectively. The enzyme was stable up to 40 degrees C and between pH 5 and 8. The isoelectric point of the enzyme was 4.3 and the Km values for p-nitrophenyl-beta-D-glucoside and p-nitrophenyl-beta-D-fucoside were 1.3 mM and 0.7 mM, respectively. This enzyme had also transferase activity for the beta-D-fucosyl group but not for the beta-D-glucosyl group. The N-terminal amino acid sequence of this enzyme was similar to those of beta-D-glucosidase from other bacteria, actinomycetes, and plants.
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PMID:Purification and characterization of beta-D-glucosidase (beta-D-fucosidase) from Bifidobacterium breve clb acclimated to cellobiose. 906 64

From a human intestinal bacterium, Eubacterium sp. A-44, which is capable of hydrolyzing saikosaponins to saikogenins, two glycosidases, beta-D-glucosidase and a novel type of beta-D-fucosidase, were isolated and characterized as saikosaponin-hydrolyzing beta-D-glucosidase and prosaikogenin-hydrolyzing beta-D-fucosidase. Relative to the hydrolyzing activities toward saikosaponins a, b1 and b2, the beta-D-glucosidase showed lower ability to hydrolyze saikosaponin d, but no ability to hydrolyze saikosaponin c or prosaikogenins. By Sephacryl S-300 column chromatography, the molecular weight of prosaikogenin-hydrolyzing beta-D-fucosidase was estimated to be about 130 kDa. The beta-D-fucosidase could hydrolyze prosaikogenins A and F, but not prosaikogenins D and G or saikosaponins. Relative to p-nitrophenyl beta-D-fucoside-hydrolyzing activity, this enzyme had 32.0% and 22.2% of its hydrolyzing ability toward p-nitrophenyl beta-D-glucoside and p-nitrophenyl beta-D-galactoside, respectively. p-Nitrophenyl beta-D-fucoside-hydrolyzing activity was inhibited by D-fucose, and was weakly inhibited by D-glucose, D-glucono delta-lactone, D-galactose and D-galactono delta-lactone. By combining these two glycosidases, saikosaponins a and b1 were converted to their saikogenins via the corresponding prosaikogenins.
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PMID:Enzymes responsible for the metabolism of saikosaponins from Eubacterium sp. A-44, a human intestinal anaerobe. 944 3

The effect of different water availabilities (water activity, aw; 0.98-0.93) and time (up to 15 days) on the production of seven hydrolytic enzymes by strains of F. moniliforme and F. proliferatum during early colonisation of gamma-irradiated living maize grain were examined in this study. Both the total activity (micromol 4-nitrophenol min(-1) g(-1) maize) and specific activity (nmol 4-nitrophenol min(-1) microg(-1) protein) were quantified using chromogenic p-nitrophenyl substrates. The dominant three enzymes produced by the fungi on whole colonised maize kernels were alpha-D-galactosidase, beta-D-glucosidase, and N-acetyl-beta-D-glucosaminidase. The other four enzymes were all produced in much lower total amounts and in terms of specific activity (beta-D-fucosidase, alpha-D-mannosidase, beta-D-xylosidase and N-acetyl-alpha-D-glucosaminidase), similar to that in uncolonised control maize grain. There were significant increases in the total production of the three predominant enzymes between 3-15 days colonisation, and between 3-6 days in terms of specific activity when compared to untreated controls. The total and specific activity of the alpha-D-galactosidase, beta-D-glucosidase and N-acetyl-beta-D-glucosaminidase, were maximum at 0.98 aw with significantly less being produced at 0.95 and 0.93 aw, with the exception of the total activity of alpha-D-galactosidase which was similar at both 0.95 and 0.93 aw. Single factors (time, aw, and inoculation treatment), two- and three- way interactions were all statistically significant for the three dominant enzymes produced except for specific activity of beta-D-glucosidase (two and three-way interactions) and for total activity of alpha-D-galactosidase in the time x aw treatment. This study suggests that these hydrolytic enzymes may play an important role in enabling these important fumonisin-producing Fusarium spp. to rapidly infect living maize grain over a wide aw range.
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PMID:Effect of water activity on hydrolytic enzyme production by Fusarium moniliforme and Fusarium proliferatum during colonisation of maize. 972 89

The ruminal fungus Caecomyces communis was grown anaerobically either in a discontinuous cultivation system or in a fermentor with daily withdrawal and addition of fresh medium. Lowe and Orpin media were tested. The best culture conditions for glycoside hydrolase production were obtained in Lowe medium with daily fresh medium addition, whereas the Orpin medium with ruminal fluid was favourable to fungal growth and to the enzyme export process. Among glycoside hydrolases assessed in both culture fluid and cellular homogenate, beta-D-fucosidase activity was preponderant. Most studied enzymes were mainly associated with cells (from 50% to 99%). Glycoside hydrolase activities were constitutive, but their level was regulated by a carbon source. beta-D-fucosidase and beta-D-xylosidase activity production was activated by the association of glucose plus cellobiose, whereas beta-D-glucosidase activity production was stimulated by cellobiose alone. Enzyme release could be favoured by glucose alone or by Ray grass hay added to glucose plus cellobiose.
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PMID:Glycoside hydrolase production by an anaerobic rumen fungus Caecomyces communis. 976 6

beta-Haemolytic, Lancefield group C streptococci within the anginosus-species group were shown by genetic and phenotypic criteria to be heterogeneous and to constitute two distinct taxa related at subspecies level to Streptococcus constellatus and Streptococcus anginosus, respectively. The first group, referred to here as DNA group 1, comprised six strains with 86-100% intragroup overall genomic DNA relatedness; five of the strains were originally isolated from the human throat and one was from an abdominal mass. They shared 61-77% DNA relatedness (delta Tm values = 1.2-1.5 degrees C) with reference strains of S. constellatus and were clearly differentiated from S. constellatus (now named Streptococcus constellatus subsp. constellatus) by the ability to produce beta-N-acetylgalactosaminidase, beta-N-acetylglucosaminidase, beta-D-fucosidase, beta-D-galactosidase and beta-D-glucosidase. The name S. constellatus subsp. pharyngis is proposed for these strains on the grounds that they are genetically and phenotypically distinct and exhibit a predeliction for the human throat, being isolated also from cases of pharyngitis. The DNA G + C content is 35-37 mol%. The type strain is MM9889aT (= NCTC 13122T). The second group (DNA group 2) was formed by five beta-haemolytic, Lancefield group C strains originally isolated from various human infections. DNA group 2 strains (81-100% intragroup DNA relatedness) shared 60-72% DNA relatedness (delta Tm values = 2.1-4.1 degrees C) with S. anginosus strains NCTC 10713T and MAS 283 but were not clearly differentiated phenotypically from S. anginosus, showed no clear pattern of clinical association, and therefore are not formally proposed as a new subspecies here.
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PMID:A study of small-colony, beta-haemolytic, Lancefield group C streptococci within the anginosus group: description of Streptococcus constellatus subsp. pharyngis subsp. nov., associated with the human throat and pharyngitis. 1055 25

Activity of the following glycosidases was detected in the plasma of the freshwater snail Biomphalaria glabrata: beta-D-fucosidase, beta-D-glucosidase, beta-D-galactosidase, beta-D-mannosidase, beta-D-glucuronidase, N-acetyl-beta-D-galactosaminidase, N-acetyl-beta-D-glucosaminidase, and lysozyme. At the physiological pH (7.2-7.4) of snail haemolymph, enzymatic activity was about 10-50% of the maximum activity at each enzyme's respective acid pH-optimum. Schistosome-susceptible B. glabrata showed lower plasma protein concentration and significantly lower enzymatic activities (U/mg protein) than schistosome-resistant snails. Changes in glycosidase activity levels correlate with the progress of infection. After successful schistosome invasion, activities of plasma glycosidases but not the concentration of total plasma proteins increased significantly during the first 2 days in both snail strains. Thus, most tegumental glycoproteins of schistosome larvae can be altered by humoral host glycosidases. The detection of only very low activities of hexosaminidases leads to the hypothesis that GalNAc/GlcNAc may be involved in the process of non-self recognition. At 4 days post-infection, glycosidase activities were identical or slightly below the levels found in naive snails. At this time of infection the parasite is encapsulated and destroyed by haemocytes of resistant snails. In susceptible snails, however, the schistosomes have transformed into sporocysts and will complete their life-cycle without eliciting effective defence reactions. After > 30 days post-infection, when cercariae are fully developed in susceptible snails, plasma protein concentration decreased significantly, whereas glycosidase activities were elevated.
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PMID:Glycosidase activities in plasma of naive and schistosome-infected Biomphalaria glabrata (Gastropoda). 1063 17

Volatile profiles and hydrolytic enzyme production by one non-mycotoxigenic and three mycotoxigenic strains of Fusarium moniliforme and F. proliferatum, grown in vitro for up to 96 h on a grain medium at 25 degrees C/0.95 water activity, were examined for differentiation of isolates. After spore lawn inoculation, measurements were made after 48, 72 and 96 h by sampling the head space above cultures with an electronic nose system using a 14 sensor surface polymer array, and by extraction and quantification of hydrolytic enzymes. There was good reproducibility of volatile patterns between replicates of the same treatment. Principal component analysis indicated that discrimination could be achieved between the uninoculated controls, the non-mycotoxigenic strain and the mycotoxin-producing strains for both species after 48 h. The total and specific activity of three out of seven enzymes (beta-D-glucosidase, alpha-D-galactosidase and N-acetyl-beta-D-glucosaminidase) were found to increase significantly in the non-mycotoxigenic when compared with the toxigenic strains of both species after 72 h. Activities of the others (beta-D-fucosidase, alpha-D-mannosidase, beta-D-xylosidase and N-acetyl-alpha-D-glucosaminidase) were not significantly different between strains. The study has shown for the first time that it is possible to differentiate between mycotoxigenic and non-mycotoxigenic strains of such spoilage fungi based on their volatile production patterns using an electronic nose system. These results have significance in the development of methods for the early detection of toxin-producing spoilage moulds in the food industry.
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PMID:Detection and differentiation between mycotoxigenic and non-mycotoxigenic strains of two Fusarium spp. using volatile production profiles and hydrolytic enzymes. 1111 57

Larval and adult Psacothea hilaris feed on mulberry wood and leaves, respectively. High levels of endogenous activity against the major dietary carbohydrates, cellulose, hemicellulose, starch and soluble sugars were secreted in the gut of larvae and adults. Activity against pectin was also high and multiple polygalacturonase (EC 3.2.1.15) components were secreted in the gut of larvae. One glycanase component, beta-EG1, which was primarily an endo-beta-1,4-glucanase (EC 3.2.1.4) and another, beta-EG2, which was mostly an endo-beta-1,4-xylanase (EC 3.2.1.8), were also secreted, while at least four additional components hydrolysed laminarin, lichenin and crystalline cellulose. The beta-glycosidase component beta-GD1 was associated with most of the beta-mannosidase (EC 3.2.1.25) and beta-xylosidase (EC 3.2.1.37) activity secreted in the gut of larvae, while another, beta-GD2, was a beta-glucosidase (EC 3.2.1.21), the activity of which was directed against cellobiose and other beta-linked disaccharides, and a beta-fucosidase (EC 3.2.1.38). A beta-galactosidase (EC 3.2.1.23), which did not hydrolyse lactose, was also secreted, as were distinct beta-N-acetylhexosaminidase (EC 3.2.1.52), trehalase (EC 3.2.1.28), alpha-L-arabinosidase (EC 3.2.1.55), alpha-galactosidase (EC 3.2.1.22) and a minimum of four alpha-glucosidase (EC 3.2.1.20) components, one of which was also likely to be associated with a peak of alpha-mannosidase (EC 3.2.1.24) activity. The alpha-glucosidase components varied in their specificity for alpha-linked disaccharides, but none was active against sucrose, which was hydrolysed by a beta-fructofuranosidase (EC 3.2.1.26) component. Overall average levels of activity in larvae were twice those of adults, but the secretion of individual carbohydrases in both was not regulated in response to the relative abundance of particular carbohydrate components in their respective diets.
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PMID:Diet and carbohydrate digestion in the yellow-spotted longicorn beetle Psacothea hilaris. 1277 Apr 76

A beta-glycosidase was purified from the seeds of Dalbergia nigescens Kurz based on its ability to hydrolyse p-nitrophenyl beta-glucoside and beta-fucoside. This enzyme did not hydrolyze various glycosidic substrates efficiently, so it was used to identify its own natural substrates. Two substrates were identified, isolated and their structures determined as: compound 1, dalpatein 7-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside and compound 2, 6,2',4',5'-tetramethoxy-7-hydroxy-7-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside (dalnigrein7-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside). The beta-glycosidase removes the sugar from these glycosides as a disaccharide, despite its initial identification as a beta-glucosidase and beta-fucosidase.
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PMID:Purification of an isoflavonoid 7-O-beta-apiosyl-glucoside beta-glycosidase and its substrates from Dalbergia nigrescens Kurz. 1609 48


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