Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.21 (beta-glucosidase)
 3,280 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Biochemical investigations were performed on autopsy tissues obtained from an 11-year-old girl who died with the juvenile, subacute neuropathic form of Gaucher disease. In addition to the expected deficiency of glucocerebrosidase activity, extracts of both liver and kidney from this individual displayed a profound (greater than or equal to 90%) deficiency of "soluble" beta-glucosidase, beta-xylosidase, and beta-galactosidase activities. Fibroblasts obtained from this individual also contained markedly reduced levels of beta-xylosidase activity but normal levels of beta-D-fucosidase and beta-galactosidase activity. Because the soluble beta-glucosidase, beta-xylosidase, and a portion of the beta-galactosidase activities from control human liver all cochromatographed on a gel filtration column of Sephadex G-200, it is suggested that these activities all reside in a single enzyme, analogous to the situation described in a number of nonhuman, mammalian tissues. This demonstration of multiple glycosidase deficiencies in addition to the deficiency of glucocerebrosidase in a case of subacute neuropathic Gaucher disease suggests that other biochemical aberrations, in addition to a deficiency of glucocerebrosidase, might contribute to pathology in some cases of Gaucher disease.
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PMID:Multiple glycosidase deficiencies in a case of juvenile (type 3) Gaucher disease. 2 87

1. Injection of a single dose of conduritol B epoxide into mice produced almost complete destruction of glucocerebrosidase (D-glucosyl-N-acylsphingosine glucohydrolase, EC 3.2.1.45) in liver, spleen, brain, and kidney within 5 h. Restoration of activity became noticeable within 1 day (2 days in the case of brain) and was about 80% of normal within 16 days. 2. The same injection produced less destruction of aryl beta-glucosidase (EC 3.2.1.21), measured at pH 5.4 with methylumbelliferyl glucoside in the absence of taurocholate. Brain showed the least amount of destruction, about 50%, but measurements of activity at lower pH values revealed complete loss of activity. This suggests that brain contains two different aryl glucosidases with differing sensitivity to the inhibitor. Liver, on the other hand, did not show differential destruction when assayed at different pH values. Resynthesis of the enzyme activities was almost complete by 16 days. 3. Injection of phenylhydrazine produced hemolysis and spleen enlargement, with concomitant increases in specific activities of glucocerebrosidase and aryl glucosidase in liver and spleen (but not in kidney). When this experiment was done in mice previously treated with conduritol B expoxide, the reappearance of cerebrosidase was found to be accelerated. This is interpreted to mean that the increased load of glucolipids from the erythrocytes had induced an enhanced synthesis of the glucohydrolase. A similar explanation may apply to aryl glucosidase and glucopeptides in the cells.
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PMID:Destruction and resynthesis of mouse beta-glucosidases. 3 20

Normal human skin fibroblasts were grown in the presence of N-hexyl-O-glucosyl sphingosine (HGS), an inhibitor of aryl glucosidase and glucocerebrosidase. Tests of the cells with aryl glycosides showed that beta-glucosidase activity in the cells was drastically reduced while other enzyme activities (alpha-glucosidase, beta-galactosidase, and N-acetyl-beta-hexosaminidase) were normal or elevated. Exposure of cells to HGS for 28 days resulted in increased values for cell weight per plate, glucocerebroside concentration, and galactosyl-galactosylglucosyl ceramide concentration. The concentrations of total lipid, cholesterol, and protein were unchanged, as was the fatty acid distribution within the glycolipids. Chemically, the inhibitor-treated cells exhibited a model form of Gaucher's disease. Although many membranous cytoplasmic inclusions were induced by HGS, they were unlike the characteristic inclusions seen in individuals with the genetic disorder. Skin fibroblasts from a Gaucher patient showed no abnormalities in composition or appearance.
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PMID:The effects of N-hexyl-O-glucosyl sphingosine on normal cultured human fibroblasts: a chemical model for Gaucher's disease. 17 14

1. The injection into mice of a single dose of conduritol B epoxide, a covalent inhibitor of glucosidases, quickly produced changes in tissue levels of beta-D-glucuronidase (EC 3.2.1.31). The specific activity of the enzyme decreased in liver, spleen and kidney while brain showed little change. The inhibitor did not act on glucuronidase in vitro, so the effect of the inhibitor is complex, possibly a result of the loss of glucosidase activity. Since glucuronidase contains glucose, we suggest that the transport of the enzyme between subcellular regions and tissues involves loss of part of the glucose moieties. 2. Levels of glucocerebrosidase (D-glucosyl-N-acylsphingosine glucohydrolase, EC 3.2.1.45) dropped very rapidly after epoxide injection, reaching a minimum at 1 h in liver. There was a noticeable restoration of activity within the next 1--2 h. Aryl beta-glucosidase (EC 3.2.1.21) decrease somewhat less than cerebrosidase, reaching a minimum within 2 h. It too showed some recovery of activity within 3 h. 3. Acid phosphatase rose slightly in liver but not in brain. alpha-L-Fucosidase and angiotensin-converting enzyme were not affected by the epoxide injection. The latter two enzymes are known to contain glucose. 4. Injection of a hemolyzing agent, phenylhydrazine, produced an increased level of glucuronidase in liver and spleen within 6 days, but not in kidney. This enhancement was a little less in mice previously injected with the glucosidase inhibitor. 5. Mice injected with the epoxide once a day eight times showed a distinct rise in brain glucuronidase level, as well as a rise in brain weight. However, the other organs showed only the same decrease in glucuronidase specific activity noted with the single injection protocol. It is suggested that the difference is due to the blood-brain barrier, which could slow the loss of brain glucuronidase from the extracellular fluid.
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PMID:Enzymic effects of beta-glucosidase destruction in mice. Changes in glucuronidase levels. 21 40

We describe three adult siblings with communicating hydrocephalus, corneal opacities, deafness, valvular heart disease, and deformed toes associated with glucosylceramide (glc-cer)-beta-glucosidase deficiency. The common manifestations of Gaucher disease were not evident. Supranuclear gaze palsies characteristic of type 3 were noted from early childhood, although the major signs were undeveloped until early adult life. Autopsy disclosed thickened leptomeninges with perivascular fibrosis, non-rheumatic calcified aortic and mitral stenosis with marked fibrosis, and mild infiltration of Gaucher cells in the reticuloendothelial organs. In contrast to the slight accumulation of glc-cer in the liver and spleen, the activity of glc-cer-beta-glucosidase was markedly decreased in the tissues, as much as in a patient with type 2 Gaucher disease. Common mutations were not found in the glucocerebrosidase gene.
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PMID:Hydrocephalus, corneal opacities, deafness, valvular heart disease, deformed toes and leptomeningeal fibrous thickening in adult siblings: a new syndrome associated with beta-glucocerebrosidase deficiency and a mosaic population of storage cells. 133 17

Cyclophellitol, a cyclitol with an epoxide, is a novel microbial secondary metabolite that inhibits beta-glucosidase and beta-glucocerebrosidase. Daily administration of cyclophellitol induces a severe abnormality of the nervous system in mice while it has no toxicity in various cultured cells. It was shown to inhibit glucocerebrosidase in vivo significantly in mice and the content of glucocerebroside in liver, spleen, and brain was increased markedly. The enzyme activity was completely suppressed in brain, liver, spleen, kidney, and muscle. On the other hand hexosaminidase activity was not affected in all tissues. After a single administration of cyclophellitol the maximal inhibition of glucocerebrosidase was observed within 30 min in brain and liver, and the inhibition lasted for 2-4 days. A single administration of cyclophellitol also induced a severe abnormality of the nervous system known as Gaucher's-like disease in mice. Conduritol B epoxide is also known to inhibit glucocerebrosidase and induce Gaucher's like-disease in mice by repetitive injection. Cyclophellitol was shown to be more potent than conduritol B epoxide in inhibition of glucocerebrosidase and in induction of the neural abnormality.
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PMID:Inhibition of glucocerebrosidase and induction of neural abnormality by cyclophellitol in mice. 138 24

Glucocerebrosidase, the lysosomal enzyme that is deficient in patients with Gaucher's disease, hydrolyses non-physiological aryl beta-D-glucosides and glucocerebroside, its substrate in vivo. We document that 2,3,-di-O-tetradecyl-1-O-(beta-D-glucopyranosyl)-sn-glycerol (2,3,-di-14:0-beta-Glc-DAG) inhibits human placental glucocerebrosidase activity in vitro (Ki 0.18 mM), and the nature of inhibition is typical of a mixed-type pattern. Furthermore, 2,3-di-14:0-beta-Glc-DAG was shown to be an excellent substrate for the lysosomal beta-glucosidase (Km 0.15 mM; Vmax. 19.8 units/mg) when compared with the natural substrate glucocerebroside (Km 0.080 mM; Vmax. 10.4 units/mg). The observations that (i) glucocerebrosidase-catalysed hydrolysis of 2,3-di-14:0-beta-Glc-DAG is inhibited by conduritol B epoxide and glucosylsphingosine, and (ii) spleen and brain extracts from patients with Gaucher's disease are unable to hydrolyse 2,3-di-14:O-beta-Glc-DAG demonstrate that the same active site on the enzyme is responsible for catalysing the hydrolysis of 4-methylumbelliferyl beta-D-glucopyranoside, glucocerebroside and 2,3-di-14:O-beta-Glc-DAG. With the aid of computer modelling we have established that the oxygen atoms in 2,3-DAG-Glc at the C-1, C-4*, C-5* (the ring oxygen in glucose) and C-2 positions correspond topologically to the oxygens at C-1, C-4* and C-5* and the nitrogen atom attached to C-2 respectively in glucocerebroside (* signifies a carbon atom in glucose); furthermore, all of the distances with respect to overlap of corresponding heteroatoms range from 0.02 A to 0.77 A (0.002-0.077 nm). A root-mean-square deviation of 0.31 A (0.031 nm) was obtained when the energy-minimized structures of 2,3-di-14:O-beta-Glc-DAG and glucocerebroside were compared using the latter four heteroatom co-ordinates.
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PMID:2,3-di-O-tetradecyl-1-O-(beta-D-glucopyranosyl)-sn-glycerol is a substrate for human glucocerebrosidase. 190 Sep 89

The authors applied the polymerase chain reaction- (PCR) based color complementation assay for rapid detection of the 1226 ("Jewish") mutation of the glucocerebrosidase gene. Fifty-seven unrelated patients with Gaucher's disease and 50 unrelated normal Ashkenazi Jewish volunteers were studied. This mutation was identified in more than 75% of the Jewish Gaucher's disease alleles and in 4 (8%) of the 50 normal Jewish volunteers. The reliability of the technique was verified both by DNA sequencing and by leukocyte beta-glucosidase assay. This method is suggested as the simplest and most suitable one for a large-scale screening for the 1226 mutation for Gaucher's disease.
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PMID:Detection of the 1226 (Jewish) mutation for Gaucher's disease by color PCR. A means for studying the gene frequency of the disorder. 234 36

This paper addresses the similarities and differences in the topology of the catalytic centres of human liver cytosolic beta-glucosidase and placental lysosomal glucocerebrosidase, and utilizes well-documented reversible active-site-directed inhibitors. This comparative kinetic study was performed mainly to decipher the chemical and structural nature of the active site of the cytosolic beta-glucosidase, whose physiological function is unknown. Specifically, analysis of the effects of a family of alkyl beta-glucosides consistently displayed 100-250-fold lower inhibition constants with the cytosolic broad-specificity beta-glucosidase compared with the placental glucocerebrosidase; for example, with octyl beta-D-glucoside the Ki values were 10 microM and 1490 microM for the cytosolic and lysosomal beta-glucosidases respectively. Furthermore the higher affinity of the cytosolic beta-glucosidase than glucocerebrosidase for the amphipathic alkyl beta-D-glucosides was validated by the greater increase in the free energy of binding with increasing alkyl chain length [delta delta G0 (K,)/CH2: lysosomal enzyme, 2.01 kJ/mol (480 cal/mol); cytosolic enzyme, 3.05 kJ/mol (730 cal/mol)]. The implications of the presence of highly non-polar domains in the active site of the cytosolic beta-glucosidase are discussed with regard to its potential physiological substrates.
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PMID:Kinetic analysis of the interaction of alkyl glycosides with two human beta-glucosidases. 250 30

Three fluorometric beta-glucosidase assays were compared for their ability to identify Gaucher's disease heterozygotes, using leukocytes as the source of enzyme: the pH 5.5-taurocholate assay of Peters et al.; the conduritol B epoxide dependent variation of that assay; and the newly developed method described herein. While the first two procedures utilize the standard substrate 4-methylumbelliferyl-beta-D-glucopyranoside to estimate beta-glucosidase activity, the new assay uses 4-heptylumbelliferyl-beta-D-glucoside as (C7UGlc) substrate. Use of this substrate enhances the specificity of the method for lysosomal glucocerebrosidase, thereby minimizing the contribution of the nonspecific cytosolic beta-glucosidase to estimates of substrate hydrolysis. Using Student's t test for the three assays examined, the C7UGlc assay procedure was determined to have the lowest p value (p less than 0.001) and highest t value (t = 4.95) for the discrimination between the mean glucocerebrosidase value of control and obligate Gaucher heterozygote samples. The high reliability and simplicity of the C7UGlc assay lends adequate reason to favor this assay for regular clinical diagnosis of Gaucher heterozygotes.
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PMID:Use of 4-heptylumbelliferyl-beta-D-glucoside to identify Gaucher's disease heterozygotes. 251 9


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