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)

Some properties of a number of enzymes immobilized by the diazotized m-diaminobenzene (dDAB) method are described. The pH-activity profiles of beta-D-glucosidase, glucoamylase, peroxidase, uricase, and D-glucose oxidase were virtually unchanged on immobilization while those of catalase and dextranase were significantly altered. beta-D-Glucosidase, glucoamylase, and glucose oxidase were found to be more susceptible to denaturation on lyophilization when immobilized than in the native state; however, sorbitol had a marked protective effect in every case examined. Sorbitol was also found to exert a stabilizing effect when lyophilized immobilized preparations were stored. Immobilization marginally improved the stabilities of a number of enzymes to heating at 60 degrees at pH 8.0. The usefulness for continuous reaction of a column of glucoamylase attached to celite was established. The reuse of the solid supports was demonstrated.
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PMID:Properties of enzymes immobilized by the diazotized m-diaminobenzene method. 1 49

Unsubstituted naphthyl substrates were found to be superior to substituted naphthyl, indolyl and hydroxyquinoline substrates for the histochemical demonstration of alpha-mannosidase, alpha-galactosidase, hetero-beta-glycosidase, glucoamylase and sucraseisomaltase, equivalent for beta-N-acetylglucosaminidase and lactase-beta-glucosidase, and inferior for beta-glucuronidase and acid beta-galatosidase. Aldehyde fixation is necessary for the localization of lysosomal glycosidases with naphthyl substrates. 1-naphthyl substrates are suitable for the detection of acid glycosidases in lysosomes and hetero-beta-glysocidase in the cytoplasm of animal cells, and 2-naphthyl substrates can be employed for the demonstration of microvillous glycosidases and for the evaluation of the total activity of soluble glycosidases with semipermeable membranes. When naphthyl substrates are used coupling should be carried out simultaneously and hexazotized pararosaniline is the coupling reagent of choice.
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PMID:Localization of glycoidases with naphthyl substrates. 5 19

The authors studied the separation of glucoamylase and beta-galactosidases from the interstinal mucosa of young rats by affinity chromatography. They tested the following chromatographic materials: p-aminophenyl-beta-D-thioglucoside bound to Sepharose 4B via hexamethylenediamine, gluconate and galactonate bound in different ways to Sepharose 4B and phlorizin bound by an azo-coupling reaction to a spacer attached to Sepharose 4B. The conditions of the adsorption of glycosidases to these materials and their subsequent elution were studied. Using chromatography on Sepharose 4B with a beta-thioglucoside affinant, we succeeded in purifying lactase preparation so that, in electrophoresis on polyacrylamide gel, it formed a single zone identical with 1-naphthyl-beta-glucosidase activity.
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PMID:Affinity chromatography of glycosidases. 61 77

Intestinal mucosa and pancreas from purebred Beagle dogs were assayed for carbohydrase activity, using several methods of tissue treatment. The enzymes found and studied were alpha-amylase, sucrase, lactase, amyloglucosidase, cellobiase, maltase, and isomaltase. Experiments using polyacrylamide gel columns and heat inactivation showed the presence of an isozyme of maltase which degrades isomaltose. This activity had not been previously demonstrated in dogs. An optimal standard procedure is presented for the preparation and assay of canine digestive enzymes. A statistical analysis of variance of the results showed that the variance was primarily associated with differences among dogs and not by variance within the procedure. When the different extraction procedures were used, results indicated that the level of enzymes detected differed with the method of treatment.
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PMID:Detection and definition of canine intestinal carbohydrases, using a standardized method. 88 14

A tetrahydroxyindolizidine alkaloid, 6,7-diepicastanospermine, was isolated from the seeds of Castanospermum australe by extraction with methanol and purified to homogeneity using ion-exchange, preparative thin-layer, and radial chromatography. A very low yield of a pyrrolidine alkaloid, N-(hydroxyethyl)-2-(hydroxymethyl)-3-hydroxypyrrolidine, was also obtained by analogous methods. The purity of both alkaloids was established by gas chromatography of their trimethylsilyl (TMS) derivatives as better than 99%. The molecular weight of each alkaloid was established as 189 and 161, respectively, by mass spectrometry, and the structure of each was deduced from their 1H and 13C NMR spectra. The structure of the pyrrolidine alkaloid is suggestive of a possible biosynthetic route to the polyhydroxyindolizidine and polyhydroxypyrrolizidine alkaloids which co-occur in C. australe. 6,7-Diepicastanospermine was found to be a moderately good inhibitor of the fungal alpha-glucosidase, amyloglucosidase (Ki = 8.4 x 10(-5) M) and a relatively weak inhibitor of beta-glucosidase. It failed to inhibit alpha- or beta-galactosidase, alpha- or beta-mannosidase, or alpha-L-fucosidase. Comparison of its inhibitory activity toward amyloglucosidase with those of its isomers, castanospermine and 6-epicastanospermine, demonstrated that epimerization of a single hydroxyl group can produce significant alteration of such inhibitory properties.
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PMID:6,7-Diepicastanospermine, a tetrahydroxyindolizidine alkaloid inhibitor of amyloglucosidase. 191 89

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

Aspergillus niger alpha-D-glucosidase, crystallized and free of detectable activity for beta-D-glucosides, catalyzes the slow hydrolysis of beta-D-glucopyranosyl fluoride to form alpha-D-glucose. Maximal initial rates, V, for the hydrolysis of beta-D-glucosyl fluoride, p-nitrophenyl alpha-D-glucopyranoside, and alpha-D-glucopyranosyl fluoride are 0.27, 0.75, and 78.5 mumol.min-1.mg-1, respectively, with corresponding V/K constants of 0.0068, 1.44, and 41.3. Independent lines of evidence make clear that the reaction stems from beta-D-glucosyl fluoride and not from a contaminating trace of alpha-D-glucosyl fluoride, and is catalyzed by the alpha-D-glucosidase and not by an accompanying trace of beta-D-glucosidase or glucoamylase. Maltotriose competitively inhibits the hydrolysis, and beta-D-glucosyl fluoride in turn competitively inhibits the hydrolysis of p-nitrophenyl alpha-D-glucopyranoside, indicating that beta-D-glucosyl fluoride is bound at the same site as known substrates for the alpha-glucosidase. Present findings provide new evidence that alpha-glucosidases are not restricted to alpha-D-glucosylic substrates or to reactions providing retention of configuration. They strongly support the concept that product configuration in glycosylase-catalyzed reactions is primarily determined by enzyme structures controlling the direction of approach of acceptor molecules to the reaction center rather than by the anomeric configuration of the substrate.
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PMID:Hydrolysis of beta-D-glucopyranosyl fluoride to alpha-D-glucose catalyzed by Aspergillus niger alpha-D-glucosidase. 219 75

Australine [(1R,2R,3R,7S,7aR)-3-(hydroxymethyl)-1,2,7-trihydroxypyrrolizid ine] is a polyhydroxylated pyrrolizidine alkaloid that was isolated from the seeds of the Australian tree Castanospermum australe and characterized by NMR and X-ray diffraction analysis [Molyneux et al. (1988) J. Nat. Prod. (in press)]. Since swainsonine and catanospermine are polyhydroxylated indolizidine alkaloids that inhibit specific glycosidases, we tested australine against a variety of exoglycosidases to determine whether it would inhibit any of these enzymes. This alkaloid proved to be a good inhibitor of the alpha-glucosidase amyloglucosidase (50% inhibition at 5.8 microM), but it did not inhibit beta-glucosidase, alpha- or beta-mannosidase, or alpha- or beta-galactosidase. The inhibition of amyloglucosidase was of a competitive nature. Australine also inhibited the glycoprotein processing enzyme glucosidase I, but had only slight activity toward glucosidase II. When incubated with cultured cells, this alkaloid inhibited glycoprotein processing at the glucosidase I step and caused the accumulation of glycoproteins with Glc3Man7-9(GlcNAc)2-oligosaccharides.
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PMID:Australine, a pyrrolizidine alkaloid that inhibits amyloglucosidase and glycoprotein processing. 249 72

Hydrocortisone administration to infant rats enhanced cellobiase and maltase activities and induced precocious expression of sucrase and trehalase activities along the length of the small intestine. These activity changes reflected proportional concentration increases in the enzymes lactase (EC 3.2.1.23), maltase/glucoamylase (EC 3.2.1.20) and sucrase-isomaltase (EC 3.2.1.48/10). Administration of an equivalent tracer dose of [3H]leucine (by body weight) to control and hydrocortisone-treated infant rats resulted in greater accumulation of label in the carbohydrase pools of the treated rats, suggesting their increased de novo synthesis. The increased concentrations of lactase and maltase/glucoamylase induced by exogenous hydrocortisone were matched by the presence of corresponding greater amounts of label in their brush border pools. Accumulation of label in each of the lactase, maltase/glucoamylase and sucrase-isomaltase pools was generally similar in the hydrocortisone-treated rats, suggesting equivalent stimulation of their synthesis as a group by the humoral agent. The turnover rates of the carbohydrases as a group were found to be similar and did not appear to differ in control and hydrocortisone-treated rats. Total protein synthesis rates were slightly greater in the intestine of the hydrocortisone-treated group of rats.
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PMID:Effects of hydrocortisone on carbohydrase concentrations, de novo synthesis and turnover patterns in immature rat intestine. 308 73

A second indolizidine alkaloid, epimeric with castanospermine, has been isolated from seeds of the Australian tree Castanospermum australe. The structure was established as 6-epicastanospermine by proton and carbon-13 nuclear magnetic resonance spectroscopy and mass spectrometry. 6-Epicastanospermine was found to be a potent inhibitor of amyloglucosidase, (an exo-1,4-alpha-glucosidase), a weak inhibitor of beta-galactosidase, and not to inhibit beta-glucosidase and alpha-mannosidase. These results indicate that glycosidase inhibitory activity cannot be predicted by comparison of the structure and stereochemistry with the appropriate sugars, since 6-epicastanospermine is an analog of mannose and not of glucose. The inhibition of amyloglucosidase was found to be competitive and to be more effective at higher pH values. Castanospermine and 6-epicastanospermine differed in their effect upon the mung bean processing enzymes, glucosidase I and II, in that the former is a potent inhibitor whereas the latter is a very poor inhibitor. Subtle alterations in stereochemistry of these alkaloids can therefore produce significant changes in their biological activity.
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PMID:6-Epicastanospermine, a novel indolizidine alkaloid that inhibits alpha-glucosidase. 309 43


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