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)

1. A third beta-glucosidase from human liver has been isolated using a mild (0.02-0.10%) Triton X-100 extraction of the exhaustively washed high speed (200,000 X g, 30 min) particulate fraction, QAE-Sephadex and concanavalin A-Sepharose chromatography. This new beta-glucosidase, referred to as TX beta-glucosidase, possesses a distinctive set of chemical properties such that it is similar to both, glucocerebrosidase and cytoplasmic beta-glucosidase, but it is not identical to either enzyme. 2. The TX beta-glucosidase hydrolyzes glucocerebroside as well as the beta-D-glucose, beta-D-galactose, beta-D-fucose, beta-D-xylose and alpha-L-arabinose derivatives of 4-methylumbelliferone. Like the cytoplasmic beta-glucosidase, the TX beta-glucosidase is inhibited by bile salts, and unaffected by conduritol B epoxide and heat stable activator protein. 3. All three beta-glucosidases were inhibited by N-hexylpsychosine, and all showed the same, mixed type inhibition kinetics, indicating a common hydrophobic binding site in all three enzymes. 4. The TX beta-glucosidase, which constitutes only a few percent of the total beta-glucosidase activity of human liver, is absent from liver from two cases of neurologic Gaucher disease and present in reduced amounts in a third case with CNS disease. Liver from a case of type 1 Gaucher disease contained normal amounts of the TX beta-glucosidase.
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PMID:Effectors of three beta-glucosidases from human liver. 681 77

The structural gene for human GBA has been assigned to chromosome 1 using somatic cell hybridization techniques for gene mapping. The human enzyme was detected in mouse RAG cell-human fibroblast cell hybrids by a sensitive double antibody immunoprecipitation assay using a mouse anti-human GBA antibody. No cross-reactivity between mouse beta-glucosidase and human GBA or GBN was observed. For the initial assignment, fifty-two primary, secondary, and tertiary man-mouse hybrids lines, derived from three separate fusion experiments, were analyzed for human GBA and enzyme markers for the human chromosomes. Without exception, the presence of human GBA in these hybrid clones was correlated with the presence of human chromosome 1 or its enzymatic markers, PGM1 and FH. All other human chromosomes were eliminated by the independent segregation of GBA and their respective enzyme markers and/or chromosomes. Using a RAG-human fibroblast line with a mouse-human rearrangement of human chromosome 1, the locus for GBA was limited to the region 1p11 leads to 1qter. Further regional localization was obtained using subclones of hybrids derived from the fusion of a human fibroblast line, 46,XX,del(1)(pter leads to q42:), with mouse RAG fibroblasts. All hybrid subclones containing a normal chromosome 1 were positive for GBA. In contrast, subclones with a single deleted chromosome 1 were negative for GBA by immunoprecipitation and by the natural substrate assays. These results further localized the gene for GBA to the narrow region, 1q42 leads to 1qter.
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PMID:Chromosomal localization of the gene for Gaucher disease. 681 85

This study explores the biochemical basis that may distinguish neurologic and nonneurologic forms of Gaucher's disease. Crude membrane preparations from spleens of controls and patients representing the three clinical categories of Gaucher's disease were delipidated by extraction with sodium cholate and n-butanol. Total beta-glucosidase activity was estimated using 4-methylumbelliferyl-beta-D-glucopyranoside (MUG) as substrate, and glucocerebrosidase activity was determined using (3H)-glucocerebroside. beta-Glucosidase and glucocerebrosidase activities were reconstituted by inclusion of sodium taurocholate or phosphatidylserine in the assay medium. When assays contained phosphatidylserine, residual beta-glucosidase activity in delipidated spleen preparations from type 1, nonneurologic cases were five times greater than cases of neurologic Gaucher's disease (82.3 vs. 11.3 units per mg protein). However, beta-glucosidase assays using sodium taurocholate did not discriminate Gaucher's disease subtypes. Similar results were obtained when spleen preparations were analyzed for glucocerebrosidase using glucocerebroside as the substrate. Brain beta-glucosidase from patients representing the three classes of Gaucher's disease showed a similar pattern of sensitivity toward phosphatidylserine. The specific activity of beta-glucosidase in an extract of brain from the one case of type 1 Gaucher's disease analyzed was five times greater than the mean residual specific activity of brain beta-glucosidase measured in five cases of type 2 and type 3 Gaucher's disease. These findings suggest that, in patients with type 1 Gaucher's disease, glucocerebrosidase may show greater activity in the presence of acidic phospholipids than glucocerebrosidase does in patients with neurologic forms of the disease. The ability of the brain enzyme from a type 1 case to be profoundly stimulated by an acidic phospholipid may explain why such individuals are spared central nervous system involvement.
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PMID:Enzymic differentiation of neurologic and nonneurologic forms of Gaucher's disease. 681 30

Autopsy samples were obtained from a 12.5-year-old girl who died with a neurologic disorder consisting of myoclonus, myoclonic epilepsy, spasticity, strabismus, and mild mental retardation but no hepatosplenomegaly. Studies in leukocytes, cultured skin fibroblasts, brain, liver, and spleen of this patient revealed glucosylceramide beta-glucosidase (EC 3.2.1.45, glucocerebrosidase) activity about 10% of controls, and well in the range found in samples from Gaucher disease patients. Extraction of the lipids from liver and spleen with chloroform-methanol (2:1) did not show accumulation of glucosylceramide or other lipid. Examination of the lipids in brain by high performance liquid chromatography revealed the presence of glucosylceramide, which is not found in brain samples from controls. Pathologic examination of the liver and spleen revealed no evidence of Gaucher disease. The brain showed many degenerative lesions and loss of neurons. There was no complementation of glucocerebrosidase activity when the cells from this patient were hybridized with cells from patients with Type 1 or Type 2 Gaucher disease. The reason for the lack of glucosylceramide storage in the liver and spleen has not been determined.
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PMID:Biochemical studies in a patient with subacute neuropathic Gaucher disease without visceral glucosylceramide storage. 685 96

Glucosylceramide: beta-glucosidase (glucocerebrosidase, EC 3.2.1.45) has been purified 12 900-fold from human placenta using a specific affinity column. The ligand, glucosyl sphingosine, prepared from glucocerebroside by alkaline hydrolysis, was attached to epoxy-activated Sepharose 6B. The enzyme was applied to the column in citrate--butanol or citrate--ethylene glycol solution at its pH optimum (5.6). No enzyme was bound in the presence of detergent. Glucocerebrosidase was eluted with citrate--taurocholate buffer at low pH or with citrate--taurocholate buffer containing D-gluconolactone at the pH optimum. Citrate--taurocholate solution alone at the pH optimum would not elute the enzyme. The enzyme hydrolyzed both the natural substrate, glucocerebroside, and the artificial substrate, 4-methylumbelliferyl glucopyranoside. Glucocerebrosidase migrated as a single band on 10% sodium dodecyl sulfate--polyacrylamide tube and (or) slab gels, corresponding to a molecular weight of 75 000. It also ran as a single zone of enzyme activity or protein on native gels, composed of 2.2% polyacrylamide--0.4% agarose containing sodium taurocholate. This is the first reported use of this gel system for the examination of glucocerebrosidase. Overall recovery is 30%. The procedure represents a more rapid and specific technique for purification of glucocerebrosidase than those previously reported.
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PMID:Purification of glucosylceramidase by affinity chromatography. 717 89

The 105 000g supernatant from human placental homogenates, prepared in the presence of sodium taurocholate and Cutscum, contained beta-glucosidase activity towards estrone glucoside as well as towards 4-methylumbelliferyl glucoside (4-MU-glucoside) and glucocerebroside. After partial purification, the estrone glucosidase was found to be active only after the addition of negatively charged phospholipid, whereas the other beta-glucosidases did not exhibit this requirement. The estrone glucosidase was separated from the 4-MU-glucosidase by chromatography on Sephadex G-200 with 0.1% sodium taurocholate in the eluting buffer. The estrone glucosidase was mainly contained in material with a pI of 4.7, while the 4-MU-glucosidase was distributed in fractions with pI values of 4.7 and 6.2 to 6.4. The partially purified estrone glucosidase had a pH optimum of 5.8, as distinct from that of 6.4 found for the 4-MU-glucosidase, and differed markedly from the 4-MU-glucosidase in its response to treatment with heat, sulfhydryl reagents, and detergents. Its sensitivity to changes in pH differed from those reported for glucocerebrosidase.
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PMID:Estrone beta-glucosidase activity in human placenta. 738 73

A method is described for the assay of glucosyl ceramide beta-glucosidase (glucocerebrosidase) in white blood cells, cultured fibroblasts and amniotic cells, and in tissue homogenates. Glucosyl ceramide extracted from Gaucher spleen and labelled by catalytically adding tritium to the ceramide double bonds was used as the substrate in the presence of pure sodium cholate as detergent. The specificity of the test was established by demonstrating the enzyme deficiency in 25 cases with Gaucher's disease type 1 and 2. In two prenatal cases quantitative liver lipid analysis showed that glucosyl ceramide storage starts in Gaucher fetuses when they are about 20 weeks old.
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PMID:Enzymic diagnosis in 27 cases with Gaucher's disease. 740 11

Restriction fragment length polymorphisms (RFLPs) were described for the porcine loci for beta-glucosidase (GBA) and the beta-polypeptide 1 of the Na+,K(+)-transporting ATPase (ATP1B1). Linkage analyses using a three-generation pedigree provided evidence for the assignment of ATP1B1, GBA and two microsatellite loci (S0001 and S0067) to a previously described linkage group comprising the loci for blood group L (EAL) and an anonymous microsatellite (S0097). The linear order of the six markers was determined with confidence by multipoint analyses and the length of the linkage group was estimated at 88cM. This linkage group was assigned to pig chromosome 4 on the basis of a previous physical localization of the ATP1B1 gene. In situ hybridization data for S0001 presented in this study were consistent with a localization on chromosome 4 and suggested a regional localization to 4p12-p13. The present study reveals conflicting data concerning the genetic localization of the K88 loci controlling the expression of the receptors for the E. coli pilus antigens. One group has reported data suggesting a loose linkage between K88 and EAL, now mapped to chromosome 4, whereas two other groups have found linkage between K88 and the transferrin locus (TF), mapped to chromosome 13 by in situ hybridization.
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PMID:A linkage group on pig chromosome 4 comprising the loci for blood group L, GBA, ATP1B1 and three microsatellites. 790 98

The basal activity of human placental glucocerebrosidase is elevated 16-fold by n-pentanol when assayed using p-nitrophenyl beta-D-glucopyranoside (pNPGlc) as the beta-glucosidase substrate. This enhancement of activity is the result of the formation of a transglucosylation product, n-pentyl beta-D-glucoside, in rate-determining competition with the hydrolytic reaction. The transglucosylation product accounts for approximately 80% of the reaction product generated in the presence of n-pentanol (0.18 M) when either glucocerebroside or pNPGlc was used as the substrate. This stimulatory effect can be increased an additional 3-fold by the inclusion of phosphatidylserine (20 micrograms/ml) or sodium taurodeoxycholate (0.3%, w/v) in the incubation medium. In the presence of retinol, glucocerebrosidase also catalyses the synthesis of a novel lipid glucoside, retinyl glucoside, when either glucocerebroside or pNPGlc serves as the substrate. The reaction product was identified as retinyl beta-D-glucoside, based on its susceptibility to hydrolysis by almond beta-D-glucosidase and the subsequent release of equimolar amounts of retinol and glucose. The rate of retinyl-beta-glucoside formation is dependent on the concentration of retinol in the incubation medium, reaching saturation at approximately 0.3 mM retinol. Retinyl beta-D-glucoside is a substrate for two broad-specificity mammalian beta-glucosidases, namely the cytosolic and membrane-associated beta-glucosidases of guinea pig liver. However, retinyl beta-D-glucoside is not hydrolysed by placental glucocerebrosidase. These data indicate that the glucocerebrosidase-catalysed transfer of glucose from glucocerebroside to natural endogenous lipid alcohols, followed by the action of a broad-specificity beta-glucosidase on the transglucosylation product, could provide mammals with an alternative pathway for the breakdown of glucocerebroside to glucose and ceramide.
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PMID:Human glucocerebrosidase catalyses transglucosylation between glucocerebroside and retinol. 800 33

The cytosolic beta-glucosidase activity that is found in a variety of mammalian tissues has no clearly defined function. In vitro assay conditions under which the broad-specificity beta-glucosidase hydrolyzes glucocerebroside at a significant rate have not been described. Nonetheless, it has been suggested that this enzyme might play an accessory role with lysosomal glucocerebrosidase in catalyzing the hydrolysis of glucosylceramide. However, this hypothesis would require that activity of both enzymes be low in severe cases of Gaucher disease in which there are pathological accumulations of glucosylceramide in one or more of the affected organs, i.e. spleen, liver and bone marrow. Information is lacking regarding the normal range of cytosolic beta-glucosidase activity in humans. p-Nitrophenyl-beta-D-mannoside was found to be a potent inhibitor (Ki = 0.068 mM) of cytosolic beta-glucosidase. In parallel studies, the activity of glucocerebrosidase was found to be minimally affected by p-nitrophenyl-beta-D-mannoside at concentrations as high as 2.5 mM. This information was used to design an assay system that would allow us to estimate glucocerebrosidase and cytosolic beta-glucosidase activities in extracts of human leukocytes. Average cytosolic beta-glucosidase activity with 4-heptyl-umbelliferyl-beta-D-glucoside as a substrate was 8.8 nmol/h/mg protein in leukocytes from 356 subjects (range, 0.2-28). Average leukocyte glucocerebrosidase specific activity was 16 nmol/h/mg protein (range 5.3-45.7). No correlation was observed between cytosolic beta-glucosidase and glucocerebrosidase activity for control and Gaucher heterozygote populations (r = 0.19 and 0.25, respectively). The wide range of leukocyte cytosolic beta-glucosidase activity in individuals tested in this study indicates that a substantial proportion of the population may lack sufficient cytosolic beta-glucosidase activity to assist a defective lysosomal glucocerebrosidase in hydrolyzing glucosylceramide.
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PMID:Variable expression of leukocyte cytosolic broad-specificity beta-glucosidase activity. 822 61


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