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)

A reproducible and convenient method for assaying glucocerebrosidase activity using the natural substrates has been developed. From the insoluble pellet fraction of cultured skin fibroblast homogenates, released glucose was measured enzymically using hexokinase coupled with the glucose-6-phosphate dehydrogenase (G6PD) and nicotinamide adenine dinucleotide phosphate (NADP) system. Optimal enzyme assay conditions required both Triton X-100 and sodium taurocholate, pH 4.8. Glucocerebrosidase activities from three patients with type 1 Gaucher disease were 17.5%, 15.8%, and 11.2% of normal (normal = 198 +/- 14 nmol/hr per mg protein, n = 3). The first patient had normal beta-glucosidase activity with the artificial fluorogenic umbelliferone substrate. Interference with the accuracy of the glucose-dependent assay system by either glycolytic or gluconeogenic enzyme activites was not detected under these experimental conditions, and when substrates with long fatty-acid chain lengths (C = 22) were used, markedly decreased glucocerebrosidase activity occurred in both normal individuals and patients. The apparent Km's for the natural substrates were 0.56 +/- 0.05 mM for controls and 2.2-3.3 mM for Gaucher fibroblasts. These data further support the hypothesis that a structurally altered and catalytically deficient enzyme is synthesized in patients with type 1 Gaucher disease and illustrate the value of the natural substrate in investigating patients.
Am J Hum Genet 1980 Sep
PMID:Gaucher disease. III. Substrate specificity of glucocerebrosidase and the use of nonlabeled natural substrates for the investigation of patients. 677 30

We have found heat inactivation of leukocyte 4-methylumbelliferyl-beta-D-glucosidase to be useful in identifying heterozygotes for adult (chronic) Gaucher's disease. The overlap between high heterozygote values and low normal values is reduced by the heat inactivation step, compared to assays without heating; that is from an overlap of 23% to 6%. Although preliminary, our results indicate that this procedure may be useful in families with adult (chronic) Gaucher's disease.
Clin Genet 1980 Sep
PMID:A modified method for the identification of heterozygotes for Gaucher's disease using differential thermal inactivation. 677 98

Three fluorometric leukocyte beta -glucosidase assays were compared for their ability to diagnose Gaucher's disease and identify carriers of the disorder: the acid beta-glucosidase assay of Beutler and Kuhl [2], a pH 5.5-sodium taurocholate-dependent assay and a new procedure which employs conduritol B epoxide, an active-site specific inhibitor of glucocerebrosidase. All three assays unambiguously identified patients with Gaucher's disease. With regard to identifying carriers the bile salt dependent assay of Peters et al. and the conduritol B epoxide-dependent procedure gave the greatest discrimination between the mean beta-glucosidase values for the control and heterozygote samples when evaluated using Student's t test. The most reliable assay for the identification of the carrier state was the conduritol B epoxide-dependent procedure which can be expected to provide the fewest false negative results when classifying heterozygotes (5%). However, the fact that none of these methods will completely separate control and heterozygote samples indicates that their use in screening programs will result in a significant number of incorrect assignments.
Clin Chim Acta 1981 Sep
PMID:An improved fluorometric leukocyte beta-glucosidase assay for Gaucher's disease. 679 54

Using glucocerebroside labeled with carbon 14 as the substrate, we determined that homogenates of brain tissue from both neuropathic and nonneuropathic cases of Gaucher's disease were profoundly deficient (more than 85%) in glucocerebrosidase activity. The beta-glucosidase activity, as measured with 4-methylumbelliferyl-beta-D-glucopyranoside as the substrate, in the homogenates of brain from four cases of Gaucher's disease was less sensitive to inhibition by conduritol B epoxide (CBE) when compared with normal brain beta-glucosidase. However, when homogenates were assayed with radiolabeled glucocerebroside as the substrate, no differential sensitivity toward CBE was indicated, suggesting the presence of an additional, CBE-insensitive, beta-glucosidase in brain tissue. Residual glucocerebrosidase activity partially purified from the brain of an adult with type 1 Gaucher's disease was activated threefold by gluconoyl hydrazine, whereas the same enzyme from control brain was unaffected, and eight times less sensitive to gluconolactone inhibition.
Arch Neurol 1982 Sep
PMID:Brain glucocerebrosidase in Gaucher's disease. 681 Aug 54

An enzymatic profile of 20 strains of Pseudomonas maltophilia was undertaken with conventional plate tests, API ZYM, and 4-methylumbelliferyl-conjugated substrates. All strains produced DNase, RNase, arbutinase, esterases and lipases, mucinase, acid and alkaline phosphatases, alkaline pyrophosphate diesterase, phosphoamidase, beta-glucosidase, leucine arylamidase, and acetatase and were hemolytic for horse, sheep, and rabbit blood. The majority of strains produced chitinase, hyaluronidase, albuminase, valine arylamidase, trypsin, alpha- and beta-glucosidases, and N-acetyl-beta-glucosaminidase. API ZYM and 4-methylumbelliferyl-conjugated substrate assays are rapid, simple, specific, and sensitive and may be useful as diagnostic aids in the identification of P. maltophilia and other pseudomonads.
J Clin Microbiol 1982 Sep
PMID:Enzymatic profile of Pseudomonas maltophilia. 681 50

The developmental profiles of four glycosidase enzymes (beta-D-glucosidase, beta-D-glucuronidase, beta-D-N-acetylglucosaminidase and beta-D-galactosidase) in the cochleas, cochlear nuclei and inferior colliculi of four strains of mice were investigated. The strains used were an audiogenically seizure-susceptible strain (DBA/2) and three non-susceptible strains (BALB/c, C3H/He and Swiss/A2G). The enzymic activities fell to varying degrees from 7 to 28 days of age. Two significant observations were made--beta-D-glucuronidase was low in the regions of the C3H/He strain, and beta-D-galactosidase was particularly low in the regions of the DBA/2 strain. The very low activity of beta-D-galactosidase in the DBA/2 mice is discussed in relation to the ganglioside patterns known to be present in these seizure-susceptible mice. Studies on the DNA contents of these auditory regions in the four strains showed no correlation with seizure sensitivity.
Neurochem Res 1982 Sep
PMID:DNA content and enzymic activities in the auditory regions of seizure-susceptible and non-susceptible strains of mice. 681 54

A heat-stable protein was isolated from the spleen of a patient with Gaucher's disease. This protein will activate glucosylceramide beta-glucosidase activity (Ho, M.W. and O'Brien, J.S. (1971) Proc. Natl. Acad. Sci. U.S.A. 68, 2810-2813). When the specificity of this activator was tested using other enzymes and substrates, it was found to activate galactosylceramide beta-galactosidase activity and sphingomyelinase but not GM1 beta-galactosidase or sulfatide sulfatase. The ability to stimulate galactosylceramide beta-galactosidase was optimum at pH 4.6 in the presence of pure phosphatidylserine or other acidic lipids such as sulfatide and phosphatidylinositol. The partially purified activator protein could stimulate galactosylceramide beta-galactosidase activity in brain, liver, leukocytes and cultured fibroblasts. It was not able to stimulate the activity of this enzyme in tissue samples from patients with Krabbe's disease, demonstrating that it was acting on galactosylceramide beta-galactosidase and not GM1 beta-galactosidase. It was slowly denatured by treatment with Pronase, reaching 16% of starting levels after 24 h at 50 degrees C. Attempts to separate the abilities of this activator preparation to stimulate several lysosomal hydrolases by column chromatography were not successful.
Biochim Biophys Acta 1982 Sep 14
PMID:A protein activator of galactosylceramide beta-galactosidase. 712 30

The kinetic regularities of glucose and cellobiose formation from microcrystalline cellulose (MCC) under the action of cellulase complexes from eight different sources were studied. By means of successive addition of selected components of the cellulase complexes (endoglucanase and cellobiase) to the reaction system the rate-limiting steps for multienzymatic hydrolysis of MCC were determined. It was shown that in most cases the rate-limiting step of glucose formation (via hydrolysis of the intermediate cellobiose) is the cellobiase action. In a single case only (with a cellulase complex from Aspergillus foetidus enriched with cellobiase) the rate of glucose formation from MCC was limited by the endoglucanase action. In accordance with the kinetic theory developed it was shown that the addition of cellobiase excess to the reaction system resulted in changes of the rate-limiting step over to endoglucanase attack on the non-soluble cellulose for all cellulase complexes under study. Under the given experimental conditions a linear correlation between the steady-state ready of glucose formation from MCC under the action of all cellulase complexes on the on hand, and the endoglucanase activity of these complexes, on the other, was established. It was shown that the action of all cellulase (arbitrarily selected ones) is described by principally the same kinetic regularities, which, in turn, is indicative of identical mechanisms for hydrolysis of the insoluble cellulose under effects of cellulase complexes of various origin.
Biokhimiia 1980 Sep
PMID:[Hydrolysis of microcrystalline cellulose by multienzyme cellulase complexes of various origins]. 724 66

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.
Clin Chim Acta 1980 Sep 08
PMID:Enzymic diagnosis in 27 cases with Gaucher's disease. 740 11

The purification of a thermostable Caldocellum saccharolyticum beta-glucosidase expressed in Escherichia coli was investigated using heat precipitation of unclarified cell homogenates. Heat treatment at 70 degrees C was capable of purification with respect to cell debris, small particulates and the majority of cell protein, although E. coli proteins were even more efficiently removed at 80 degrees C and above. For thermostable proteins expressed in E. coli, a precipitation temperature of 80 degrees C or greater is recommended for optimal removal of contaminant proteins. In small-scale heating trials, heating rate was found to influence enzyme yield significantly. Losses were minimised when 'flash-heating' was employed. The successful single-step removal of particulates, labile protein and nucleic acids was achieved by simultaneous heat-treatment and polyethyleneimine addition, although the purification achieved was additive rather than synergistic.
J Biotechnol 1995 Sep 29
PMID:Optimising the recovery of recombinant thermostable proteins expressed in mesophilic hosts. 757 36


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