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)

1. The enzyme beta-glucosidase (beta-D-glucoside glucohydrolase, EC 3.2.1.21) from the gut contents of active Achatina achatina exists in two molecular forms, beta-glucosidase C (mol.wt. about 82000) and D (mol.wt. about 41000). 2. Only the lower-molecular-weight species was found in the gut contents of aestivating snails or in extracts from their digestive glands and washed gut walls. 3. On re-activation of some aestivating snails, betion of ATP and Mg2+ to the isolated gut contents or to extracts from washed gut walls led to the formation of higher-molecular-weight forms of the enzyme, beta-glucosidase A (mol.wt. about 329000) and beta-glucosidase B (mol.wt. about 165000). 5. All these forms of the enzyme have similar pH optimum (pH 5.0-5.6). 6. The Michaelis constants (Km) and heat stability of the enzyme increased with increasing molecular complexity.
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PMID:The beta-glucosidase in the gut contents of the snail Achatina achatina. 0 70

An energy-dependent polymerization-depolymerization phenomenon in the beta-glucosidase (beta-D-glucoside glucohydrolase, EC 3.2.1.21) in the gut contents of the giant African snail Achatina achatina has been observed. The formation of the octamer, tetramer and dimer from the monomer (mol. wt. approx. 41 000) and vice versa are catalysed by proteins in the present gut contents.
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PMID:Metabolic regulation of beta-glucosidase in the gut content of the snail Achatina achatina. 93 85

This study was undertaken to measure the liberation in vitro of ellagic acid [2], a naturally occurring inhibitor of carcinogenesis, from precursor ellagitannins under conditions found in the gut tract. Enzymes, namely beta-glucosidase, esterases, and alpha-amylase, were incubated with raspberry extract. In addition, raspberry extract and casuarictin [1] were treated at different pH's and with the contents of small intestine and cecum from rats fed AIN-76A diet. The esterase activity of the enzyme samples was measured spectrophotometrically using p-nitrophenol acetate as the substrate, and the amount of ellagic acid [2] released from all samples was analyzed by hplc. The hydrolysis of the ellagitannins was not catalyzed by any of the purified enzymes tested, and components of the raspberry extract were found to inhibit the purified esterases noncompetitively. Casuarictin [1] was hydrolyzed to yield high quantities of ellagic acid [2] when placed in buffer at pH 7 and 8, or when incubated with cecal contents for two hours. The release of ellagic acid [2] from the raspberry extract was optimal at pH 8, and maximal release in cecal contents occurred with 1 h. Small intestinal contents had no significant effect on ellagic acid liberation from either casuarictin [1] or raspberry extract.
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PMID:The effects of pH and rat intestinal contents on the liberation of ellagic acid from purified and crude ellagitannins. 179 80

Gastric intubation was adopted as a means of comparing the effect of two feeding levels, continuous nutrient supply (C) and restricted nutrient supply (R), on the digestive development of pigs weaned at 14 d of age, during the first 5 d post-weaning. The absolute weights of the stomach and the pancreas were significantly greater (P less than 0.001) in C compared with R pigs. The effect was not significant for pancreas weight when expressed per kg body-weight but was significant (P less than 0.05) for stomach weight. The weights of the small intestine (SI), SI mucosa and total mucosal protein were significantly higher (P less than 0.001) in C pigs but protein content per g mucosa was similar in the C and R groups. There was no significant effect of treatment on the activity of lactase (beta-glucosidase; EC 3.2.1.23) or sucrase (sucrose-alpha-glucosidase; EC 3.2.1.48) irrespective of the basis of comparison used. The specific activity (mumol/min per g protein) of maltase (alpha-glucosidase; EC 3.2.1.20) and of glucoamylase (glucan-1,4-alpha-glucosidase; EC 3.2.1.3) were similar in C and R groups but activities of maltase (mumol/g mucosa) (P less than 0.05), and maltase and glucoamylase (mol/d) (P less than 0.01) were significantly higher in C pigs. Villous height and crypt depth were significantly greater in C pigs (P less than 0.001 and P less than 0.05 respectively). Enteroglucagon was significantly (P less than 0.05) higher in C compared with R pigs. Xylose absorption and the digestibility of energy were not affected by treatment. Digestibility of dry matter, organic matter, crude protein (nitrogen x 6.25) and carbohydrate were significantly higher (P less than 0.001, P less than 0.01, P less than 0.05 and P less than 0.001 respectively) in R pigs compared with C pigs but the differences were small, ranging from 1.3 to 2.5%. These results demonstrate that (1) nutrient intake in the weaned pig affects the anatomy, morphology and function of the gut, (2) there is considerable 'spare capacity' for digestion of cereal-based diets even in pigs weaned at 14 d of age, (3) measurements in vitro of digestive function are of limited value unless supported by information in vivo on absorption/digestibility.
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PMID:Digestive development of the early-weaned pig. 2. Effect of level of food intake on digestive enzyme activity during the immediate post-weaning period. 204 2

The intestinal first pass metabolism of amygdalin has been investigated in rat small intestine in vitro. The results show that amygdalin is hydrolyzed to prunasin, essentially in the wall of the proximal jejunum. This specific beta(1-6)hydrolytic cleavage of the terminal glucose residue is pH-dependent and can be inhibited by glucono-delta-lactone, a potent inhibitor of the lysosomal beta-glucosidase of the rat intestine. No substrate competition between phloridzin and lactose vs amygdalin was noted. None of the more common soluble beta- or alpha-enzymatic activities of mammalian intestine (alpha-glucosidase, alpha-amylase) or mammalian liver (beta-galactosidase, beta-glucuronidase) were capable of catalyzing the hydrolysis of the terminal glucose from amygdalin at pH's 5.0, 7.0 or 9.0. Furthermore, no metabolic activity of isolated rat livers toward amygdalin and prunasin was observed within two hours of recirculating perfusion. However, cecal contents of conventional rats, exhibited both amygdalin- and prunasin-hydrolyzing activities. The resulting mandelonitrile dissociates spontaneously into cyanide and benzaldehyde. Therefore, our findings indicate that metabolism of amygdalin to prunasin occurring in the proximal part of jejunum is apparently mediated by enzymatic beta(1-6)glucosidase activity of the gut wall. In contrast, the toxicity of amygdalin due to the release of cyanide obviously requires microbiological activities of the gut flora.
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PMID:Intestinal first pass metabolism of amygdalin in the rat in vitro. 308 25

1. The thio-beta-d-glucosiduronic acids (thio-beta-glucuronides) of o-aminothiophenol, diethyldithiocarbamic acid, p-nitrothiophenol and thiophenol are formed biosynthetically in broken- and intact-cell preparations of mouse liver. 2. For this biosynthesis to occur in homogenates or microsomal fractions, UDP-glucuronic acid was required during incubation; glucose, glucuronic acid or UDP could not replace it. UDP was a product of the reaction. 3. The biosynthetic mechanism linking glucuronic acid to thiol and carbodithioic groups therefore requires UDP-glucuronyltransferase activity and resembles that forming the various types of O-glucuronides. 4. An analogous enzymic mechanism employing UDP-glucose synthesizes the thio-beta-d-glucosides of diethyldithiocarbamic acid and thiophenol in gut preparations of the mollusc Arion ater; this mechanism resembles that forming the O-glucosides. The thio-beta-d-glucosides are formed also in intact cells. 5. As expected from the distribution of O-glycosides, S-glucuronides of these aglycones were not detectable with the invertebrate, nor were the S-glucosides with the vertebrate. 6. Despite their similar biosyntheses, S- and O-beta-glycosides differ in susceptibility to hydrolysis by beta-glycosidases. Rat preputial-gland beta-glucuronidase hydrolysed thioglucuronides of o-aminothiophenol, diethyldithiocarbamic acid and p-nitrothiophenol, hydrolysis being inhibited by glucarolactone; the thioglucuronide of thiophenol was not hydrolysed by preputial-gland or liver beta-glucuronidase. The two S-glucosides resisted hydrolysis by beta-glucosidase from almond emulsin.
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PMID:Mechanism of biosynthesis of thio- -D-glucuronides and thio- -D-glucosides. 465 87

A fibre-free diet, or the same diet supplemented with 100 g cabbage or carrot cell-wall preparation/kg, was fed to rats for 28 days and the activities of a number of caecal microbial enzymes (azoreductase, aryl nitroreductase, beta-glucosidase, beta-glucuronidase, imidazole nitroreductase and nitrite reductase) were determined in vitro. The plant cell-wall preparations diluted the gut contents and decreased the number of bacteria per gram of caecal contents. Enzyme activities per gram of caecal contents were also decreased, with the exception of beta-glucosidase activity which was significantly increased. These plant cell-wall preparations also increased caecal size, and thereby significantly increased total activity per caecum of microbial azoreductase, aryl nitroreductase, beta-glucosidase and beta-glucuronidase. When bacterial metabolism was expressed per 10(9) bacteria, all enzyme activities were significantly increased in caecal samples from rats fed the plant cell-wall preparations. There was an overall concordance of 0.91 between all the enzymes when expressed per 10(9) bacteria, but of only 0.38 when enzyme activities were expressed per gram of caecal contents.
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PMID:Metabolic profile of caecal micro-organisms from rats fed indigestible plant cell-wall components. 629 83

beta-D-Mannosidase (beta-D-mannoside mannohydrolase EC 3.2.1.25) was purified 160-fold from crude gut-solution of Helix pomatia by three chromatographic steps and then gave a single protein band (mol. wt. 94,000) on SDS-gel electrophoresis, and three protein bands (of almost identical isoelectric points) on thin-layer isoelectric focusing. Each of these protein bands had enzyme activity. The specific activity of the purified enzyme on p-nitrophenyl beta-D-mannopyranoside was 1694 nkat/mg at 40 degrees and it was devoid of alpha-D-mannosidase, beta-D-galactosidase, 2-acetamido-2-deoxy-D-glucosidase, (1 leads to 4)-beta-D-mannanase, and (1 leads to 4)-beta-D-glucanase activities, almost devoid of alpha-D-galactosidase activity, and contaminated with less than 0.02% of beta-D-glucosidase activity. The purified enzyme had the same Km for borohydride-reduced beta-D-manno-oligosaccharides of d.p. 3-5 (12.5mM). The initial rate of hydrolysis of (1 leads to 4)-linked beta-D-manno-oligosaccharides of d.p. 2-5 and of reduced beta-D-manno-oligosaccharides of d.p. 3-5 was the same, and o-nitrophenyl, methylumbelliferyl, and naphthyl beta-D-mannopyranosides were readily hydrolysed. beta-D-Mannobiose was hydrolysed at a rate approximately 25 times that of 6(1)-alpha-D-galactosyl-beta-D-mannobiose and 6(3)-alpha-D-galactosyl-beta-D-mannotetraose, and at approximately 90 times the rate for beta-D-mannobi-itol.
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PMID:beta-D-Mannosidase from Helix pomatia. 683 86

Cycasin, methylazoxymethanol-beta-glucoside, is a naturally occurring carcinogenic compound. The genotoxicity of cycasin was assayed in the Drosophila wing spot test. Cycasin induced small single and large single spots on feeding at 10 mumol/g medium. The presence of these spots indicates that cycasin is genotoxic in Drosophila melanogaster. Microorganisms which showed beta-glucosidase activity for cleaving cycasin to toxic aglycon were isolated from gut flora of the Drosophila larvae. Consequently, the Drosophila wing spot test would be useful for mutagenicity screening of other naturally occurring glucosides.
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PMID:Genotoxic activity in vivo of the naturally occurring glucoside, cycasin, in the Drosophila wing spot test. 770 Feb 78

In order to determine the origin of cellulases in the gut of the earthworm Eisenia fetida andrei, the wall tissues of the different parts of the disinfected gut are cultured in vitro. Enzymatic activities (FPase: filter paper activity; CMCase: carboxymethycellulase, cellobiase) were measured both in the tissues and in the culture medium: the following activities were found, carboxymethycellulase (CMCase), filter paper activity (FPase). The first located in the crop, gizzard and midgut wall, the second in the foregut and midgut wall. The cellobiase was detected only in the crop and gizzard tissues, whereas it is present in each part of the gut of holoxenic worms. This fact indicates that this enzyme is mainly produced by microorganisms ingested. These results allow us to propose the hypothesis of the existence of synergy, for the cellulose hydrolysis between tissular enzymes and cellulolytic microorganisms.
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PMID:[Contribution to the study of the origin of cellulase activities of the gut in earthworm Eisenia fetida andrei]. 909 Nov 82


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