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)

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

An enzyme has been isolated from human liver by DEAE-cellulose chromatography and has been shown by competitive substrate inhibition to be capable of hydrolysing synthetic beta-D-galactosides, beta-D-glucosides, beta-D-fucosides, beta-D-xylosides, and alpha-L-arabinosides. Another form of alpha-L-arabinosidase activity elutes with the major beta-D-galactosidase component on DEAE-chromatography, but has a different identity on the basis of its stability at 4 degrees C. Liver samples from patients with Gaucher's disease are deficient in beta-D-fucosidase as well as beta-D-glucosidase activity.
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PMID:The common identity of five glycosidases in human liver. 126 36

A beta-D-glycosidase activity was purified from mycelium of Humicola grisea var. thermoidea grown on avicel as the main carbon source. The purified enzyme was a glycoprotein and migrated as a single polypeptide band on polyacrylamide gel electrophoresis under native or denaturing conditions. The apparent molecular weight of the enzyme was estimated to be 55 kDa by gel filtration and SDS-PAGE. The enzyme was active against o-nitrophenyl beta-D-galactoside; p-nitrophenyl beta-D-glucoside, p-nitrophenyl beta-D-fucoside, lactose and cellobiose, PNP fucoside (synthetic substrate) and cellobiose (natural substrate) being the best utilized. A comparison of the properties of beta-D-galactosidase, beta-D-glucosidase and beta-D-fucosidase showed that three activities exhibited similar pH and temperature optima and the same thermostability. The hydrolysis rate of substrate mixtures suggests that the enzyme possesses a common catalytic site for all the substrates assayed.
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PMID:Beta-D-glycosidase activities of Humicola grisea: biochemical and kinetic characterization of a multifunctional enzyme. 210 72

Two enzymes that hydrolysed lactose were purified essentially to homogeneity from cell extracts of the oleaginous yeast Trichosporon cutaneum. One enzyme of Mr 120,000 had properties typical of a beta-galactosidase (EC 3.2.1.23). It hydrolysed lactose, lactulose and nitrophenyl-beta-D-galactosides. The enzyme required K+ or Rb+ for activity, and other monovalent cations tested were not effective. Enzyme activity was abolished by EDTA and stimulated by Mg2+, Mn2+ and Ca2+. The beta-galactosidase was induced by lactose, galactose, lactulose and lactobionic acid. The other enzyme, a beta-glycosidase (EC 3.2.1.21) of Mr 52,000 showed no ionic requirements and it hydrolysed lactose, nitrophenyl-beta-D-galactosides, 4-nitrophenyl-beta-D-glucoside, cellobiose, laminaribiose, laminaritriose and sophorose, but not gentiobiose, 4-nitrophenyl-beta-D-mannoside or sucrose. This enzyme was induced by lactose, galactose and lactulose, and also by cellobiose.
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PMID:Purification and properties of two lactose hydrolases from Trichosporon cutaneum. 212 10

A neutral beta-galactosidase has been purified by concanavalin A-Sepharose affinity chromatography, DEAE-cellulose chromatography, Sephadex G-200 gel filtration and hydroxylapatite chromatography. The enzyme was purified 126-fold with a yield of about 21%. This form has a neutral optimal pH (7.5) and it is located in the cytosolic fraction. It shows a wide pH stability from pH 4.5 to 8.0, but it is very unstable at low pH values. Its isoelectric point is 4.9 and this value does not change on neuraminidase treatment. The estimated molecular weight was 47 000. The neutral form shows beta-D-galactosidase, beta-D-fucosidase and beta-D-glucosidase activities, all of them associated in a single peak in all the purification steps. p-Nitrophenyl beta-D-galactosides, p-nitrophenyl beta-D-fucosides and p-nitrophenyl beta-D-glucosides competed fully for a common active site in mixed-substrate experiments. Using gamma-D-galactonolactone as competitive inhibitor the Ki values were always coincident for the three activities. The effect of NaCl, methyl mannoside and some sugars (fucose, galactose and glucose) was studied.
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PMID:Properties and kinetics of a neutral beta-galactosidase from rabbit kidney. 301 54

Because kidney microangiopathy with capillary basement membrane thickening has been reported in spontaneous hypertension, we have studied the activities of three lysosomal glycosidases able to degrade the carbohydrate moieties of basement membrane constituents in the kidney cortex of 12-week-old spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar Kyoto rats (WKY). These activities were also determined in SHR and WKY treated from 6 to 12 weeks of age with hydralazine (mean dose, 18 mg/kg per day in drinking water). Sialidase specific activity on sialyl-alpha 2-3-[3H]lactitol was markedly decreased in the kidney of untreated SHR, 40% activity remaining relative to that found in untreated age-matched WKY (p less than 0.001). beta-Galactosidase specific activity on p-nitrophenyl-beta-D-galactoside was also decreased, 86% activity remaining relative to that found in untreated WKY (p less than 0.001). Glucosyl-galactosyl-hydroxylysyl glucohydrolase specific activity on glucosyl-galactosyl-hydroxylysine was equally diminished, 74% activity remaining relative to that found in untreated age-matched WKY (p less than 0.001). In contrast, the activities of two control glycosidases inactive on the carbohydrate moieties of basement membrane constituents, alpha-glucosidase assayed with p-nitrophenyl-alpha-D-glucoside as substrate and beta-glucosidase assayed with p-nitrophenyl-beta-D-glucoside as substrate, were significantly increased. All the alterations in enzyme activities observed in the kidney of SHR were also present in the long-term treated normotensive SHR. No effect of the hydralazine treatment on the three enzyme activities investigated could be demonstrated in the WKY. Thus the alterations observed in the kidneys of SHR appear to be independent of blood pressure level.
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PMID:Alteration in sialidase and other glycosidase activities in the kidney of spontaneously hypertensive rats: persistence after preventive treatment with hydralazine. 321 99

The influence of prodrug structure on specificity of glycoside/glycosidase based colon-specific drug delivery was studied by preparing nine steroid glycosides, measuring their relative lipophilicities, and hydrolyzing them with bacterial glycosidases from rat intestines. The 21-yl beta-D-glucosides and galactosides of dexamethasone, prednisolone, hydrocortisone, and fludrocortisone and the 21-yl beta-D-cellobioside of prednisolone were prepared by a modified Koenigs-Knorr reaction. The deacetylated glycoside prodrugs, along with the P-nitrophenyl derivatives of beta-D-glucoside, galactoside, and cellobioside, were subjected to hydrolysis by the contents of the rat stomach, proximal small intestine (PSI), distal small intestine (DSI), and cecum. All the prodrugs were hydrolyzed slowly by PSI and stomach contents, more rapidly by contents of the DSI, and most rapidly by cecal contents. This is the basis of the site-specific drug delivery reported earlier (Friend, D. R.; Chang, G. W. J. Med. Chem. 1984, 27, 261). Furthermore, the prodrugs themselves had very different susceptibilities to hydrolysis. Hydrolysis rates catalyzed by DSI contents decreased in the following order: prednisolon-21-yl beta-D-galactoside (10) greater than prednisolon-21-yl beta-D-glucoside (2) greater than prednisolon-21-yl beta-D-cellobioside (13) greater than dexamethason-21-yl beta-D-galactoside (9) greater than dexamethason-21-yl beta-D-glucoside (1). Hydrolysis of cellobioside 13 was only half that of glucoside 2 and one-fourth that of galactoside 10. Hydrolysis of all the prodrugs in cecal contents was rapid, with the exceptions of hydrocortison-21-yl beta-D-glucoside (5) and fludrocortison-21-yl beta-D-glucoside (7), which were hydrolyzed more slowly than the other glucoside prodrugs. Eadie-Hofstee plots for hydrolysis of the glucoside compounds suggested that bacterial beta-D-glucosidase activity in the colon may be more heterogeneous in nature than beta-D-galactosidase activity. Relative lipophilicities of the prodrugs and free steroids were compared by measuring their octanol-buffer partition coefficients (P). The logarithm of the P of cellobioside 13 (-0.56) was considerably lower than that of the other prodrugs, which ranged from 0.11 to 0.84. Log P of the free steroids ranged from 1.54 to 1.73. These relative rates of hydrolysis and relative lipophilicities, along with previously reported animal experiments, enable one to estimate the site specificity of glycoside prodrugs prior to extensive animal studies.
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PMID:Drug glycosides: potential prodrugs for colon-specific drug delivery. 396 14

The midgut caecal cells from Rhynchosciara americana larvae possess a plasma-membrane-bound beta-D-glucosidase (cellobiase, EC 3.2.1.21), which is recovered (75-95%) in soluble form both after treatment with Triton X-100 and after treatment with papain. The Triton X-100-solubilized beta-D-glucosidase displays Mr106000 and pI 5.4, whereas the papain-released beta-D-glucosidase shows Mr65000 and pI 4.7. Thermal inactivations of the detergent-solubilized and the papain-released forms of beta-D-glucosidase both follow apparent first-order kinetics with similar half-lives. The papain-released beta-D-glucosidase, after being purified by density-gradient centrifugation, hydrolyses beta-D-glucosides, beta-D-galactosides and beta-D-fucosides at the same active site, as inferred from experiments of competition between substrates. The beta-D-glucosidase seems to operate in accordance with rapid-equilibrium kinetics, since the Km (0.61 mM) for the enzyme is constant over a wide range of pH. The hydrolysis of the beta-D-glucosidic bond catalysed by the beta-D-glucosidase occurs without inversion of configuration, delta-gluconolactone is a strong (Ki 0.5 microM) inhibitor of the enzyme and substituents in the substrate aglycone affect the catalytic constant of the reaction. These data support the assumption that the mechanism of the reaction catalysed by the beta-D-glucosidase involves the intermediary formation of a carbonium ion, rather than a glucosyl-enzyme intermediate.
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PMID:Physical and kinetic properties of a plasma-membrane-bound beta-D-glucosidase (cellobiase) from midgut cells of an insect (Rhynchosciara americana larva). 641 80

beta-Glucosidase (beta-D-glucoside glucohydrolase, EC 3.2.1.21) splitting p-nitrophenyl-beta-D-glucosidase was isolated from cellular preparation of the fungus Geotrichum candidum 3c "cellocandine G10x" and purified 38-fold. The enzyme was homogeneous during ultracentrifugation, gel-filtration, isoelectrofocusing and disc-electrophoresis in polyacrylamide gel and had a pI of 4.2, sedimentation coefficient of 2.6S and molecular weight of 120 000. The enzyme had maximal activity at pH 5.6, 45 degrees and retained up to 45% of its activity under optimal conditions (pH, t degrees) after 48 hr incubation. beta-Glucosidase did not split disaccharides, e. g. lactose cellobiose, laminaribiose, gentibiose as well as o-nitrophenyl-beta-D-galactoside, methyl-beta-D-xyloside. The enzyme hydrolyzed p-nitrophenyl-beta-D-glucopyranoside (Km = 0.18 mM) and some plant beta-glucosides, such as phenylethyl-beta-D-glucopyranoside from rose petals and diosgenine tetrasaccharide from deltoid dioscorea (Km = 0.26 mM).
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PMID:[Properties of beta-glucosidase from the cellulolytic fungus Geotrichum candidum 3c]. 680 88


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