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)

The optimal reaction conditions and kinetic properties of eleven leukocyte acid hydrolases determined with the use of fluorigenic derivatives of 4-methyl-umbelliferone are described. The enzymes studied were acid phosphatase, aryl sulfatase, alpha- and beta-glucosidase, alpha- and beta-galactosidase, alpha-mannosidase, N-acetyl-beta-glucosaminidase, N-acetyl-beta-galactosaminidase, beta-glucuronidase and alpha-fucosidase. More than 90% of the activity of each enzyme was released into a 27,000 X g supernatant by a double sonication procedure employing 0.9% sodium chloride and 0.1% Triton X-100. The Km values obtained were similar to those previously reported for chromogenic subtrates. A single Km value could not be derived for beta-galactosidase because its double reciprocal plot was not linear. All enzymes could be measured with less than 10 mug of protein within 15 min. Activators and inhibitors studied included the chloride salts of Na+, K+, Zn2+, Ca2+, Mg2+, Hg2+, and Fe2+ as well as p-chloromercuriphenysulfonate, glutathione, BAL, EDTA, EGTA, Triton X-100 and sodium taurocholate. The reaction conditions described in this report can be used for the diagnosis of various lysosomal storage diseases and should facilitate the development of automated procedures for the analysis of these eleven enzyme activities with small quantities of blood.
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PMID:Human leukocyte acid hydrolases: characterization of eleven lysosomal enzymes and study of reaction conditions for their automated analysis. 0 26

Two isozymes of membrane-bound beta-glucosidase (beta-D-glucoside glucohydrolase, EC 3.2.1.21) with activity towards 4-methylumbelliferyl-beta-D-glucopyranoside have been identified in human cells. One of these isozymes was found to have a pH optimum of 5.0, a Km of 0.4 mM and to be rapidly inactivated at pH 4.0 ("acid-labile"). The second isozyme had a pH optimum of 4.5, a Km of 0.8 mM and was stable at pH 4.0 ("acid-stable"). Cultured long-term lymphoid lines and peripheral blood leukocytes contained both isozymes while cultured skin fibroblasts contained only the "acid-stable" form in detectable amounts. The specific activity of the "acid-stable" isozyme was severely reduced in cultured skin fibroblasts, cultured long-term lines and peripheral leukocytes from patients with Gaucher's disease. The specific activity of the "acid-labile" enzyme in the latter two cell types was apparently unaffected. The beta-glucosidase activity in all three cell types examined was predominantly particulate but the enzyme could be solubilized with low concentrations of Triton X-100. The solubilized enzyme required sodium taurocholate (0.2%) for maximum activity. Solubilized beta-glucosidase did not exhibit the cell-specific differences in pH optimum and Km shown by the membrane-bound enzyme.
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PMID:Cell-specific differences in membrane beta-glucosidase from normal and Gaucher cells. 1 44

Cultured human skin fibroblasts from normal and glucosylceramidotic subjects are found to contain one beta-glucoside hydrolase as compared with multiple enzymes in other tissues. The fibroblast enzyme has an approximate molecular weight of 150,000 under isotonic conditions, as determined by gel filtration. It occurs as a large aggregate at low ionic strength. Ceramide, 4-methylumbelliferyl, and p-nitrophenyl beta-glucosides are active as substrates. The enzyme in whole cell homogenates is membrane-bound and is solubilized by a combination of Triton X-100 and sodium taurocholate. It has a pH optimum at 4.2 and no demonstrable divalent cation requirement. The cultured fibroblast beta-glucosidase displays close similarity to one of the forms of beta-glucosidase in human spleen, specifically that form which is affected in Gaucher's disease. 4-Methylumbelliferyl beta-glucosidase activity in homozygous fibroblasts from infantile and adult forms of Gaucher's disease are reduced to 9 and 14%, respectively, of normal fibroblast activity. The residual activity in the lipidotic cells shows increased heat lability, but cannot be distinguished from that in normal cells with respect to gel exclusion properties, Michaelis constant, and pH dependence.
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PMID:beta-Glucoside hydrolase activity of normal and glucosylceramidotic cultured human skin fibroblasts. 1 34

Membrane-bound beta-glucosidase from cultured skin fibroblasts can be solubilized in an active form by treatment of membrane preparations with a mixture of Triton X-100 and sodium taurocholate. Several properties of the solubilized enzyme have been studied in fibroblasts from normal, healthy individuals and from 14 patients with different clinical forms of Gaucher disease. The patients studied were classified as follows: group 1 consisted of 10 chronic patients, all (with one exception) of Ashkenazi Jewish origin; group 2 consisted of three black American patients with severe visceral symptoms, manifest from early childhood, but with no apparent neurological involvement; and group 3 consisted of a single white patient with the classical infantile form of the disease. Specific beta-glucosidase activity ranged from 6.6% to 16.5% mean control value in group 1 patients and from 4.1% to 5.8% in groups 2 and 3. When compared with the enzyme from control fibroblasts, the enzyme from chronic Gaucher patients (group 1) was more rapidly inactivated at 50 degrees C, had an altered pH curve, was less effectively inhibited by deoxycorticosterone-beta-glucoside, and was more effectively inhibited by deoxycorticosterone. The enzyme from patients in groups 2 and 3 was qualitatively indistinguishable from the control enzyme in terms of these parameters. No differences in Km (4-methylumbelliferyl-beta-glucoside) or sedimentation coefficient were found between the beta-glucosidases from control and Gaucher cells. The results demonstrate that cells from Ashkenazi Jewish patients with the chronic form of Gaucher disease contain a structurally altered form of beta-glucosidase. This enzyme differs both from normal beta-glucosidase and from the residual enzyme in patients of different ethnic origin and with clinically more severe forms of the disease.
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PMID:Properties of beta-glucosidase in cultured skin fibroblasts from controls and patients with Gaucher disease. 10 89

Some of the properties of a partially purified particle bound and soluble beta-glucosidase (EC 3.2.1.21) from pig kidney were compared. The soluble beta-glucosidase (1) hydrolyzed 4-methylumbelliferyl-beta-D-glucoside (4-MU-beta-D-glucoside) 17 alpha-estradiol 3beta-glucoside. 17 alpha-estradiol 17beta-glucoside, and salicin, but not glucosylceramide, (2) possessed a broad pH optimum (5.5-7.0), (3) had an isoelectric point of 4.9, and (4) was inhibited by Triton X-100. Several compounds were found to be competitive inhibitors of its hydrolytic activity, gluconolactam and estrone beta-glucoside being the most effective. In contrast, a particulate beta-glucodidase purified from the same tissue (1) had an acidic pH optimum (5.0), (2) was stimulated by sodium taurocholate and 'Gaucher's factor' for the hydrolysis of both 4-MU-beta-glucosidase and glucosylceramide, and (3) was capable of catalyzing a transglucosylation reaction employing 4-MU-beta-D-glucoside or glucosylceramide as the glucosyl donor, and [14C]ceramide as acceptor.
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PMID:The beta-glucosidases of porcine kidney. 19 Nov 59

The latency of the alpha-glucosidase activity of intact rat liver lysosomes was studied by using four substrates (glycogen, maltose, p-nitrophenyl, alpha-glucoside, alpha-fluoroglucoside) at a range of substrate concentrations. The results indicate that the entire lysosome population is impermeable to glycogen and maltose, but a proportion of lysosomes are permeable to alpha-fluoroglucoside and a still higher proportion permeable to p-nitrophenyl alpha-glucoside. Incubation at 37 degrees C in an osmotically protected buffer of of pH 5.0 caused lysosomes to become permeable to previously impermeant substrates and ultimately to release their alpha-glucosidase into the medium. The latencies of lysosomal beta-glucosidase and beta-galactosidase were examined by using p-nitrophenyl beta-glucoside and beta-galactoside as substrates. The results indicate permeability properties to these substrates similar to that to p-nitrophenyl alpha-glucoside. On incubation in an osmotically protected buffer of pH 5, lysosomes progressively released their beta-galactosidase in soluble form, but beta-glucosidase remained attached to sedimentable material. Lysosomal beta-glucosidase was inhibited by 0.1% Triton X-100; alpha-glucosidase and beta-galactosidase were not inhibited.
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PMID:Latency of some glycosidases of rat liver lysosomes. 101 43

Effect of different concentration of non-ionic detergents (Triton X-100, Triton X-305, BRIJ-35 and Triton WR-1339) on total and non-sedimentable activity of 8 rat liver lysosome enzymes (acid phosphatase, acid DNase, acid RNase, arylsulphatases A and B, beta-glucuronidase, beta-galactosidase, beta-glucosidase and beta-acetylglucosaminidase) was studied. Only Triton X-100 at the concentration of 0.1% (and higher) was found to release completely lysosome enzymes. Low concentrations of Triton X-100 (0.025-0.05%) were used to characterize the strength of enzyme binding: the level of releasing acid DNase, beta-galactosidase, beta-glucuronidase and acid phsophatase being considerably higher than that of other lysosome enzymes studied. On the basis of the data obtained a method is worked out, which is suitable for series studies of the stability of lysosome membranes under different physiological and pathological conditions. The essence of the method is the treatment of membrane particles with increasing concentrations of Triton X-100 (0.025; 0.05 AND 0.1%) AND THE SUCCESSIVE ESTIMATION OF NON-Sedimentable activity of marker enzymes. The method detected troubles in the stability of rat liver lysosome membranes under starvation, protein deficiency and aging.
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PMID:[Determination of lysosome membrane stability]. 120 72

An extracellular laminarinase (1----3)-beta-glucan glucohydrolase (EC 3.2.1.6) was purified from culture filtrates of Penicillium funiculosum. It was homogeneous on polyacrylamide gel electrophoresis in the presence and absence of sodium dodecyl sulfate. It had a Mr of 14,000 and isoelectric point of pH 4.2. The apparent Km value for lamimarinase was 8.3 mg/ml and Vmax was 8 mumol/min/mg. The distribution of beta-glucosidase activity in two different species of Penicillium showed that P. funiculosum had a higher ratio of extracellular to cell wall bound activity than Penicillium janthinellum. Treatment of mycelia of both species with NaCl, EDTA, Triton X-100, or proteolytic enzymes did not release the cell wall bound beta-glucosidase. Incubation of the mycelia with the laminarinase released 2-4 times more beta-glucosidase than the estimated cell bound activity in P. janthinellum and P. funiculosum.
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PMID:Laminarinase from Penicillium funiculosum and its role in release of beta-glucosidase. 190 46

Human lysosomal beta-glucosidase (D-glucosyl-acylsphingosine glucohydrolase, EC 3.2.1.45) is a membrane-associated enzyme that cleaves the beta-glucosidic linkage of glucosylceramide (glucocerebroside), its natural substrate, as well as synthetic beta-glucosides. Experiments with cultured cells suggest that in vivo this glycoprotein requires interaction with negatively charged lipids and a small acidic protein, SAP-2, for optimal glucosylceramide hydrolytic rates. In vitro, detergents (Triton X-100 or bile acids) or negatively charged ganglioside or phospholipids and one of several "activator proteins" increase hydrolytic rate of lipid and water-soluble substrates. Using such in vitro assay systems and active site-directed covalent inhibitors, kinetic and structural properties of the active site have been elucidated. The defective activity of this enzyme leads to the variants of Gaucher disease, the most prevalent lysosomal storage disease. The nonneuronopathic (type 1) and neuronopathic (types 2 and 3) variants of this inherited (autosomal recessive) disease but panethnic, but type 1 is most prevalent in the Ashkenazi Jewish population. Several missense mutations, identified in the structural gene for lysosomal beta-glucosidase from Gaucher disease patients, are presumably casual to the specifically altered posttranslational oligosaccharide processing or stability of the enzyme as well as the altered in vitro kinetic properties of the residual enzyme from patient tissues.
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PMID:Acid beta-glucosidase: enzymology and molecular biology of Gaucher disease. 212 41

A membrane-bound alpha-L-fucosyltransferase, which is involved in the synthesis of a developmentally regulated carbohydrate antigen, SSEA-1, was purified about 2000-fold from F9 embryonal carcinoma cells. The procedures used were solubilization with Triton X-100, column chromatography on SP-Sephadex, DEAE-Sephadex, RCA-agarose and on GDP-agarose. Upon sodium dodecyl sulfate gel electrophoresis, the purified preparation gave a protein band with a relative molecular mass of 65 000. The optimum pH of the enzyme was between 6.0 and 7.0 and the Km toward N-acetyllactosamine was 0.55 mM. The enzyme was active with asialofetuin, but not with intact fetuin. Susceptibility of the product to alpha-L-fucosidase I from almond emulsin verified that the enzyme transferred fucose to C-3 hydroxyl of N-acetylglucosamine in the N-acetyllactosamine structure. Activities of beta-galactoside alpha 1----2-fucosyltransferase and N-acetylglucosaminide alpha 1----4-fucosyltransferase acting on synthetic substrates were not detected in the purified enzyme nor in the crude extract of F9 cells. PYS-2 parietal endoderm cells lacked all the fucosyltransferases mentioned above.
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PMID:Purification and properties of N-acetylglucosaminide alpha 1----3-fucosyltransferase from embryonal carcinoma cells. 242 30


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