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)

The crystalline style of the gastropod Telescopium telescopium contains two (1 linked to 3)-beta-D-glucanases and a beta-D-glucosidase. The two glucanases (I and II) have been purified and shown to be endo-enzymes. Both enzymes attack laminarin, carboxymethylpachyman, and lichenin, but have no action towards carboxymethyl-cellulose. The main products of hydrolysis of laminarin are D-glucose and beta-(1 linked to 3)-linked oligosaccharides of d.p. 2, 3, and 4. Glucanases I and II are similar to each other, although they differ in molecular weight and kinetic properties.
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PMID:Purification and characterisation of two endo-(1 linked to 3)-beta-D-glucanases from Telescopium telescopium. 48 66

The problem of melaninogenesis and quinone tanning of the cuticle was examined by histochemical and biophysical methods (electroparamagnetic resonance: EPR) on normal subjects of Pycnoscelus surinamensis and on subjects with abnormal cuticular colour. The cuticle of abnormal subjects showed a lower content of polyphenolic substances and a greater positivity for the indole group. This suggests that in these insects tanning products can be synthetized differently and not derived from tyrosine but from tryptophan as postulated by Pryor (1955). Furthermore, a higher number of unsaturated aminic groups is found in abnormal subjects. Granules present only in the cytoplasm of the epidermal cells of the abnormal newly moulted subjects may indicate that the polyphenolic compound of tanning, secreted in an inactive form as 4-O, beta-glucoside, is not freed from the beta-glucosidase and remains as such in the cytoplasm.
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PMID:Histochemical and biophysical study of cuticle sclerotization in Pycnoscelus surinamensis L. (Blattaria). 53 16

Homogenates of liver and kidney tissue from young steers had beta-D-glucosidase (EC 3.2.1.21) activity toward 17alpha-estradiol-3-glucoside, 17beta-estradiol-3-glucoside, 17alpha-estradiol-17-glucoside, and deoxycorticosterone-21-glucoside. The activity towards the phenolic 3-glucosides was largely present in the 100 000 X g supernatant, while that towards 17alpha-estradiol-17-glucoside was concentrated in the microsomes. The use of beef liver preparations for the hydrolysis of steroid 'glucuronide' fractions could result in hydrolysis of other steroid glycosides which might be present.
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PMID:Steroid beta-D-glucosidase in steer liver and kidney. 83 45

Calf pancreas microsomes incorporated radioactively labeled D-glucose from UDP-D-glucose into products extracted with chloroform/methanol (2:1, v/v), chloroform/methanol/water (10:102.5, v/v), and into the residual precipitate, with a pH optimum in Tris/maleate buffer of about 5.3. The chloroform/methanol extract contained a single 14C-labeled acidic product, which was identified as dolichyl beta-D-glucosyl phosphate. It was stable to mild alkali, yielded D-[14C]glucose upon mild acid hydrolysis, and a 14C-labeled compound with the chromatographic mobility of 1,6-anhydro-beta-D-glucopyranosyl upon hot alkali treatment. The [14C]glucolipid had the same chromatographic mobility as dolichyl beta-D-[14C]mannosyl phosphate, and its formation was stimulated by exogenous dolichyl phosphate. The chloroform/methanol/water extract contained radioactive lipid-bound oligosaccharides which were retained on DEAE-cellulose more strongly than dolichyl D-[14C]glucosyl phosphate. They were stable to mild alkali, but labile to acid and hot alkali. Acid treatment yielded a D-glucose-labeled oligosaccharide fraction which was shown by gel filtration to be slightly larger than most of the D-mannose-labeled oligosaccharides. About 80% of the radioactive D-glucose residues could be removed with alpha-glucosidase, but not with beta-glucosidase. Pancreatic dolichyl beta-D-[14C]glucosyl phosphate incubated with calf pancreas microsomes served as direct donor of D-glucosyl residues to lipid-bound oligosaccharides and to the precipitate. These oligosaccharides had the same size as those labeled from UDP-D-[14C]glucose, and the D-[14C]glucose residues could also be removed with alpha-glucosidase.
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PMID:Glucosyltransferase activity in calf pancreas microsomes. Formation of dolichyl D[14C]glucosyl phosphate and 14C-labeled lipid-linked oligosaccharides from UDP-D-[14C]glucose. 84 29

A procedure to test beta-glucosidase was developed for identification of the mycobacteria. One hundred and thirty-three strains representing 17 species were assayed in a buffered system containing whole cells and the substrate p-nitrophenyl-beta-D-glucoside. Qualitative differences between species indicated that the test was useful in discriminating among the mycobacteria.
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PMID:beta-Glucosidase activity in mycobacteria. 85 67

A purified beta-D-glucosidase (beta-D-glucoside glucohydrolase, EC 3.2.1.21) isozyme isolated from almond emulsin was found to catalyze hydrolysis of beta-D-glucopyranosides and beta-D-galactopyranosides but not the corresponding alpha-D-derivatives. Hydrolysis of the corresponding beta-D-thioglycopyranosides at rates 10(3)--10(4) times lower than those for the hydrolysis of the beta-D-glycopyranosides was also noted. The enzyme does not exhibit any transferolytic activity using D-glucose or D-galactose as acceptors. D-glucose, p-nitrothiophenyl-beta-D-glucopyranoside, 5-deoxy-5-thio-D-glucose and D-glucono-delta-lactone are shown to exert mainly competitive inhibition on beta-D-galactopyranoside hydrolysis. D-galactose, p-nitrothiophenyl-beta-D-galactopyranside and methylthio-beta-D-galactopyranoside are shown to inhibit the glucopyranoside hydrolysis mainly non-competitively and to exert competitive inhibition of galactopyranoside hydrolysis. The inhibition caused by the antibiotic Nojirimycin (5-amino-5-deoxy-D-glucose) is shown to be more complex. Analysis of the kinetic data indicates that the catalytic site of the enzyme responsible for the beta-D-glucosidase activity is kinetically distinct from the beta-D-galactosidase site.
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PMID:Studies on almond emulsin beta-D-glucosidase. II. Kinetic evidence for independent glucosidase and galactosidase sites. 86 Dec 29

A unique demonstration is presented of the capacity of glycosidases to create anomeric configuration de novo. Purifed Candida tropicalis alpha-glucosidase and sweet almond beta-glucosidase have been found to attack the same substrate, D-glucal, and to convert this unusual glycosyl substrate (which lacks alpha or beta anomeric configuration) to 2-deoxy-alpha-(or beta-) D-glucose, respectively. The stereospecificity of the hydration reaction catalyzed by each enzyme in D2O was revealed by the use of high-resolution (270 MHz) 1H magnetic resonance spectroscopy. The alpha-glucosidase caused a specific axial protonation (deuteration) of D-glucal at C-2, and formation of 2-deoxy-alpha-D-[2(a)-2H]glucose. The beta-glucosidase catalyzed an oppositely directed axial protonation at C-2 and formation of 2-deoxy-beta-D-[2(e)-2H]glucose. These results are not accounted for by the generally accepted mechanisms of carbohydrase action derived from studies with glycosidically linked substrates alone. D-Glucal apparently binds to the enzymes with essentially the same overall orientation as the D-glucosyl moiety of glycosidically linked substrates (with the double bond of D-glucal lying essentially in the plane of the similarly bound D-glucosyl group). Thus, the alpha-glucosidase evidently protonates D-glucal from above the double bond and alpha-D-glucosidic substrates from below the glycosidic oxygen; beta-glucosidase apparently protonates D-glucal from below the double bond and beta-D-glucosides from above the glycosidic oxygen. A detailed mechanism is proposed for the hydration of D-glucal by each enzyme, involving an incipient glycosyl carbonium ion and assuming the presence at the active site of two carboxyl groups arranged to account for catalysis of glycosylations from glycosidically linked substrates. That D-glucal serves as a glycosyl substrate for these enzymes strongly supports the concept that glycosidases and glycosyltransferases are catalysts of glycosylation (i.e., glycosylases), since this concept does not make the usual assumption that carbohydrases are restricted to acting on substrates having a glycosidic bond and either alph- or beta-anomeric configuration.
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PMID:Scope and mechanism of carbohydrase action: stereospecific hydration of D-glucal catalyzed by alpha- and beta-glucosidase. 87 25

beta-Glucosidase activity was measured in control subjects and in five patients with neuropathic Gaucher's disease. In three patients with Gaucher's disease, methylumbelliferyl- and p-nitrophenyl-beta-d-glucopyranoside (4MU- and PNP-beta-glucosidase) activity was almost normal in the liver but markedly reduced in the spleen and fibroblasts. In the other patients with Gaucher's disease 4MU- and PNP-beta-glucosidase activity was also very much reduced in the liver, spleen, and fibroblasts. DEAE-cellulose column chromatography with a chloride gradient elution of the liver extract from a control subject and from two patients with Gaucher's disease, exhibiting normal 4MU- and PNP-beta-glucosidase activity, revealed the presence of two peaks of 4MU- and PNP-beta-glucosidase activity (fractions 1 and 2). pH activity curves of beta-glucosidases and Km measured with 4MU-beta-glucoside in fractions 1 and 2 from patients with Gaucher's liver were identical to those from the control liver. However, fractions 1 and 2 from infantile Gaucher's liver exhibited no activity measured with glucocerebroside whereas those from juvenile Gaucher's liver showed a considerable activity. Glucocerebroside was greatly accumulated in the liver, even though an almost normal activity of 4MU-beta-glucosidase was detected in three of the five patients studied.
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PMID:Neuropathic Gaucher's disease with normal 4-methylumbelliferyl-beta-glucosidase activity in the liver. 87 Aug 71

In comparison with 1- and 2-naphthyl beta-D-glucoside, beta-D-galactoside, beta-D-glucuronide, beta-D-N-acetylglucosaminide, alpha-D-glucoside, alpha-D-galactoside and alpha-D-mannoside 1- and 2-naphthyl alpha-L-fucoside are hydrolyzed more quickly or to the same extent by homogenates prepared from freeze-dried cryostate sections of various rat organs. Nevertheless, when the fucosides are employed for the histochemical demonstration of alpha-L-fucosidase mostly negative data were obtained independent on the method used, whereas all other naphthyl glycosies deliver positive results. The reasons for these discrepancies are the marked inhibition of alpha-L-fucosidase by aldehyde fixation and diazonium salts. Then, alpha-L-fucosidase activity is suppressed to 90% and between 85 and 98% respectively; the inhibition of alpha- and beta-D-glucosidase, alpha- and beta-D-galactosidase, alpha-D-mannosidase, beta-D-glucuronidase and beta-D-N-acetylglucosaminidase by the fixative or coupling reagent does not exceed 70%. Therefore 1- and 2-naphthyl alpha-L-fucoside cannot be recommended in general for histochemical purposes. Small amounts of dimethylformamide do not influence the activity of most of the glycosidases investigated. For biochemical measurements, however, especially 1-naphthyl alpha-L-fucoside represents a suitable alternative in a fluorometric procedure instead of p-nitrophenyl alpha-L-fucoside used for the photometric evaluation of alpha-L-fucosidase. With the fluorometric method the enzyme was measured in rat organs, which posses remarkably different activities of alpha-L-fucosidase.
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PMID:[Suitability of naphthyl-alpha-L-fucosides for the investigation of alpha-L-fucosidases (author's transl)]. 88 38

A number of adsorbents useful for purifying glycosidases were synthesized and their adsorption and characteristics were examined using partially purified glycosidase mixtures from Takadiastase or soybean. These adsorbents were prepared by coupling di-epsilon-aminocaproyl-p-aminophenyl N-acetyl-1-thio-beta-D-glucosaminide, beta-D-glucoside, beta-D-galactoside or alpha-D-mannoside with CNBr-activated Sepharose 4B. Many glycosidases were adsorbed on the four adsorbents at low ionic strength, and increase of the ionic strength caused the enzymes to be eluted. However, the specificity of the adsorbents, contrary to our expection, was very low. All of these adsorbents adsorbed Taka N-acetyl-beta-D-glucosaminidase [EC 3.2.1.30], Taka beta-D-glucosidase [EC 3.2.1.21], and Taka beta-D-galactosidase [EC 3.2.1.23] at low ionic strength. The order of elution of these three enzymes by a linear gradient of ionic strength was the same in the four adsorbents, the order being beta-D-galactosidase, beta-D-glucosidase, and N-acetyl-beta-D-glucosaminidase. Soybean glycosidases also showed nearly the same elution pattern, though the ionic strength of the eluate was slightly lower than with Taka glycosidases. Soybean alpha-D-mannosidase [EC 3.2.1.24] was also adsorbed on these adsorbents, and was eluted between beta-D-glucosidase and N-acetyl-beta-D-glucosaminidase. These adsorption phenomena were not specific as regards the structure of the glycoside moiety, but they were useful for purifying glycosidases, possessing good reproducibility with easy activation and mild operating conditions.
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PMID:Affinity chromatography of glycosidases. Preparation and properties of affinity column adsorbents. 94 2


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