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 radiation inactivation method was used to determine the molecular weight of membrane-bound neutral sphingomyelinase from normal human brain. Inactivation curves showed a molecular mass of 167,000 +/- 32,000. Molecular weights of two control enzymes, beta-N-acetylglucosaminidase and nonspecific beta-glucosidase, determined by the same procedure, were consistent with previous reports.
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PMID:Molecular weight of human brain neutral sphingomyelinase determined in situ by the radiation inactivation method. 298 32

Lymphoid cell lines established by Epstein-Barr Virus (EBV)-transformation of peripheral blood B-lymphocytes from patients affected with type 1 Gaucher disease showed a severe deficiency of glucosylceramide-beta-glucosidase activity (residual activity around 15%-30% of control activity). Ultrastructural investigations showed, in these lymphoid cell lines from type 1 Gaucher disease, the presence of numerous membrane-bound inclusion bodies characteristic of Gaucher cells.
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PMID:Biochemical and ultrastructural findings in Epstein-Barr virus-transformed lymphoid cell lines from type 1 Gaucher disease. 303 33

Lymphoid cell lines (LCL) from 3 adult patients with non-neuropathic Gaucher disease were established by Epstein-Barr virus (EBV) transformation and were investigated from the view of enzymology. Glucosylceramide-beta-glucosidase (GlcCer-beta-glucosidase) was present in soluble and particulate fraction of LCL from normal subjects and was deficient in type 1 Gaucher LCL; the deficiency of all molecular forms, shown by electrofocusing, indicates that they are coded by the same gene. The existence of two non-specific beta-glucosidases, one soluble (minor), the other membrane-bound (major), was demonstrated in leucocytes and LCL from normals; in Gaucher LCL, these were also present in a normal range. Characteristic properties of the non-specific membrane-bound beta-glucosidase were defined: lability at acidic pH and strong inhibitory effect by detergents. These properties allowed to discriminate it from the lysosomal GlcCer-beta-glucosidase and to define optimal assay conditions for determination of residual GlcCer-beta-glucosidase activity in Gaucher disease, using artificial substrate, without interference of non-specific membrane-bound beta-glucosidase. These results demonstrate that EBV-transformed LCL represent an accurate model system for enzymatic studies of Gaucher disease.
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PMID:beta-Glucosidase isoenzymes in Epstein-Barr virus-transformed lymphoid cell lines from normal subjects and patients with type 1 Gaucher disease. 303 13

The behaviour of highly purified glucosylceramide beta-glucosidase (glucosylceramidase, EC 3.2.1.45) from human placenta [Furbish, F. S., Blair, H. E., Shiloach, J., Pentchev, P. G. & Brady, R. B. (1977) Proc. Natl Acad. Sci. USA 74, 3560-3563] was investigated in the absence of detergents with structurally modified glucosylceramides inserted into unilamellar liposomes. The reaction between the water-soluble enzyme and the liposomal substrates was significantly dependent on the structure of the lipophilic aglycon moiety of glycolipids: glucosyl-N-acetyl-sphingosines (D-erythro and L-threo) were better substrates than the corresponding glucosylceramides. The L-threo derivatives were poorer substrates with higher apparent Km values than the corresponding D-erythro derivatives. For glucosyl-3-keto-ceramide and glucosyl-dihydro-ceramide (D-erythro), higher Km values were found than for glucosylceramide. Sphingosine, glucosylsphingosine and glucosyl-N-acetyl-sphingosine were the most effective inhibitors of the hydrolysis of glucosylceramide. D-erythro-Ceramide and D-galactosyl-N-acetyl-D-erythro-sphingosine inhibited the hydrolysis of amphiphilic glucosylceramide but not that of water-soluble 4-methyl-umbelliferyl-beta-glucoside, suggesting a hydrophobic binding site of the enzyme for the aglycon moiety of its membrane-bound substrate. Dilution experiments suggested that at least a fraction of the enzyme associates with the liposomes and degrades the lipid substrate even in the absence of activator proteins. Acidic phospholipids incorporated into liposomes caused a powerful stimulation (30-40-fold) of the glucosylceramide beta-glucosidase, whereas acidic sphingolipids (sulphatide, gangliosides GM1 and GD1a) incorporated into liposomes stimulated this enzyme only moderately (3-10-fold).
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PMID:Specificity of human glucosylceramide beta-glucosidase towards synthetic glucosylsphingolipids inserted into liposomes. Kinetic studies in a detergent-free assay system. 378 Jul 20

1. Glucocerebrosidase, in association with a membrane-bound ;acid' beta-glucosidase, was separated from a soluble ;neutral' beta-glucosidase that had no activity towards glucocerebroside as substrate. 2. Glucocerebrosidase, as well as ;acid' beta-glucosidase activity depended upon the association of factor P (a heat-stable, soluble, acidic glycoprotein) with factor C (a heat-labile membrane-bound protein). 3. Factor C was solubilized under certain conditions. 4. Solubilized factor C, as well as membrane-bound factor C, could be alternatively stimulated by sodium taurocholate to give both glucocerebrosidase and ;acid' beta-glucosidase activities. 5. Membrane-bound factor C reacted optimally with factor P whereas solubilized factor C was preferentially stimulated by taurocholate. 6. Factor P-dependent glucocerebrosidase activity differed in kinetic properties from the taurocholate-stimulated enzyme activity. 7. The results are discussed in the light of (a) identity of glucocerebrosidase and ;acid' beta-glucosidase, (b) application in clinical diagnosis, (c) physiological significance of the enzyme system, and (d) polygenic inheritance in adult Gaucher's disease.
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PMID:Identity of 'acid' beta-glucosidase and glucocerebrosidase in human spleen. 478 Jun 97

The biosynthesis of cholesteryl glucoside by Mycoplasma gallinarum strain J proceeds by the transfer of glucose from uridine-5'-diphosphoglucose to membrane-bound sterol. Galactose also can be coupled to cholesterol via uridine-5'-diphosphogalactose. The reaction is specific for the uridine-5'-diphospho sugars. Enzymatic activity is associated with the membrane. Treatment of the membrane to remove endogenous sterol inactivates the enzyme. Only sterol which has been bound to the membrane participates in the reaction. The optimum pH is about 8.0, and Mg(2+) is required. The reaction is unaffected by nucleotide triphosphate, uridine-5'-monophosphate, and uridine-5'-diphosphate. Reduction of pH to the optimum for beta-glucosidase in the membrane results in loss of synthesized glucoside. The enzyme is saturated at 0.5 mm uridine-5'-diphosphoglucose. The apparent K(m) of 2.05 x 10(-7) indicates a high affinity of the enzyme for the nucleotide sugar.
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PMID:Biosynthesis of cholesteryl glucoside by Mycoplasma gallinarum. 513 38

The radiation inactivation method has been used to compare the molecular weight of the nonspecific membrane-bound beta-glucosidase in situ in normal human spleen and in that of two patients with Gaucher disease type 1. We report, in type 1 Gaucher spleen, the presence of a high molecular weight component (557 000) in addition to the normal low molecular weight component (97 800). The various possible hypotheses explaining this high molecular weight component are discussed.
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PMID:Modifications of the molecular weight of membrane-bound nonspecific beta-glucosidase in type 1 Gaucher disease determined in situ by the radiation inactivation method. 623 54

Cationic amphiphilic drugs, which include tricyclic antidepressants, have been shown to give rise to lipidoses under experimental conditions, with a general increase of lipids especially phospholipids. We report here an early and important decrease in sphingomyelinase activity in C6 glioma cells cultured in the presence of imipramine or desipramine at final concentrations of 0.01 and 0.05 mM. The effect was both dose-dependent and time-dependent and was observed before any lipid accumulation. Cerebroside beta-glucosidase and cerebroside beta-galactosidase had normal activities under the same experimental conditions and thus there was no general effect on membrane-bound sphingolipid hydrolases. A decrease of sphingomyelinase activity has been previously reported for two amphiphilic compounds, perhexiline maleate and AY 9944. These results suggest a potential function of sphingomyelinase in the mode of action of these drugs.
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PMID:Effect of tricyclic antidepressants on sphingomyelinase and other sphingolipid hydrolases in C6 cultured glioma cells. 630 26

Conditions are described for the preparation of permeabilized cells of Candida albicans. This method has been used for the in situ assay of enzymes in both yeast cells and germ-tube forming cells. A mixture of toluene/ethanol/Triton X-100 (1:4:0.2, by vol.) at 15% (v/v) and 8% (v/v) was optimal for the in situ assay of glucose-6-phosphate dehydrogenase in yeast and germ-tube forming cells, respectively. The concentration of toluene/ethanol/Triton X-100 required for optimal in situ activity of other enzymes was influenced by the cellular location of the enzyme, growth phase and morphology. The membrane-bound enzymes (chitin synthase, glucan synthase, ATPase), cytosolic enzymes (glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase, pyruvate kinase, phosphofructokinase, alkaline phosphatase, glucosamine-6-phosphate deaminase and N-acetylglucosamine kinase) and wall enzymes (beta-glucosidase and acid phosphatase) were measured and compared to the activity obtained in cell extracts. The pattern of enzyme induction and the properties of the allosteric enzymes phosphofructokinase and pyruvate kinase were measured in situ. Pyruvate kinase in situ was homotropic for phosphoenolpyruvate with a Hill coefficient of 1.9 and a S0.5 of 0.6 mM, whereas in cell extracts, it had a Hill coefficient of 1.9 and a S0.5 of 1.0 mM. The Km for ATP was 1.6 mM in cell extracts and 1.8 mM in permeabilized cells. In situ phosphofructokinase was homotropic for fructose 6-phosphate (S0.5 of 2.3 mM, Hill coefficient of 4.0). The kinetic properties of pyruvate kinase and phosphofructokinase measured in situ or in vitro were similar for both yeast cells and germ-tube forming cells.
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PMID:The in situ assay of Candida albicans enzymes during yeast growth and germ-tube formation. 631 58

The radiation inactivation method has been used to determine the molecular mass of membrane-bound acid beta-glucosidase (EC 3.2.1.21) in situ, in normal human spleen and in that of two patients with type I Gaucher disease: the molecular mass in Gaucher spleen is about double (125 000 +/- 8900) of that found in the normal spleen (67 000 +/- 7700) which is compatible with the existence of subunit coupling in the muted acid beta-glucosidase. From the results, we conclude that subunit interaction is altered in mutant acid beta-glucosidase and that this may be due to a direct effect of the mutation.
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PMID:Modification of subunit interaction in membrane-bound acid beta-glucosidase from Gaucher disease. 641 92


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