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

---

Query: EC:3.2.1.21 (beta-glucosidase)
3,280 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
...
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.
...
PMID:beta-Glucoside hydrolase activity of normal and glucosylceramidotic cultured human skin fibroblasts. 1 34

In in vitro tests with lysosomes isolated from the liver and kidneys of castrated rats of both sexes the action of testosterone and beta-estradiol in concentrations of 3.76.10(-4)M on the activity of beta-glucosidase, beta-galactosidase and acid phosphatase was investigated. Testosterone is shown to reduce the total and free activity of the membrane-bound enzymes and to increase the release from the matrix lysosomes. Estradiol proved less active than is testosteron. The renal lysosomes in vitro are more sensitive to the action of sex hormones than are hepatic lysosomes. In the interaction of testosterone and estradiol with lysosomal membranes a sex specificity was revealed.
...
PMID:[The effects of testosterone and estradiol on the activity of lysosomal enzymes in rat liver and kidneys]. 9 95

The activity of the membrane-bound enzymes of the microvillous zone of the entreocytes (maltase, sucrase, trehalase, lactase, cellobiase, alkaline phosphatase and leucylaminopeptidase) was studied in mucosal smears from the proximal jejunum, ileum, caecum and sigmoid flexure in a group of control (C) (8) and germ-free (GF) (7) rabbits. The trypsin and chymotrypsin activity of the contents of the ileum, caecum and sigmoid flexure was studied in 6 C, 5 GF and 5 monocontaminated (MC) rabbits. In summing up it can be stated that the individual membrane-bound enzymes have a different gradient in the various intestinal segments of C and GF rabbits and that they differ reciprocally in character. The maximum statistically significant differences between GF and C rabbits were found in the ileum; in the jejunum they were somewhat smaller and in the caecum smaller still (in this localization the difference was C versus GF). Striking differences in the proportion of the individual disaccharidases were found inthe jejunum and ileum of C rabbits compared with GF rabbits, in which, in both these segments of small intestine the relationship maltase greater than sucrase greater than trehalase greater than lactase was preserved. The proteolytic activity of the intestinal contents likewise had a different gradient character in C, MC and GF rabbits. The maximum activities (especially trypsin) were found in MC animals. The microbial flora is one of the factors regulating the enzymatic activities of the microvillous zone of the enterocytes and it also significantly influences the proteolytic activity of the intestinal contents. This influence is particularly marked in the distal part of the alimentary tube.
...
PMID:Digestive enzymes of the mucosa of the small intestine and trypsin and chymotrypsin proteolytic activity of the intestinal contents of germ-free, monocontaminated and conventional rabbits. 35 55

Tissues of rats with adjuvant arthritis manifested differences in activity and distribution between free, latent and membrane-bound forms of acid catepsins, alpha-D- and beta-D-galactosidases, alpha-D- and beta-D-glucosidases, beta-D-glucorunidase, hyaluronidase, acid phosphatase, arylsulphatases (A+B). Activation of certain hydrolytic enzymes is observed in tissues of the liver, kidneys, heart and spleen: a rise in total activity (of arylsulphatase in the liver and acid catepsins in the spleen; hyaluronidase in the kidneys, beta-D-glucuronidase in the heart) and a change in the ratio of different forms with a simultaneous increase in the activity of free form (of hyaluronidase in the spleen, acid phosphatase in the heart and liver). Inhibition of alpha-D-glucosidase in the liver and beta-D-glucosidase in the spleen is also detected. A decrease in the activity of beta-D-glucuronidase in the spleen is pronounced in a significant decrease in the activity of each enzyme free form with no changes in the total activity.
...
PMID:[Hydrolytic enzymes of rat tissues with adjuvant arthritis]. 72 90

The effect of the mycotoxin of Fusarium sporotrichiella v. sporotrichioides (sporofusarin) was studied in vitro on the total and nonsedimenting activity of eight lysosomal enzymes: acid ribonuclease, aryl sulfatases A and B, beta-glucuronidase, alpha- and beta-galactosidases, beta-glucosidase, beta-acetylglucosaminidase, and alpha-mannosidase. Incubation of a suspension of rat liver lysosomes with an aqueous solution of sporofusarin led to inhibition of the total activity of the membrane-bound lysosomal enzyme beta-glucosidase. In a dose of only 1.6 x 10-5 M sporofusarin caused a significant increase in the nonsedimenting activity of nearly all the enzymes; in a concentration of 1.6 x 10-3 M most of the enzymes of the lysosomal matrix (beta-glucuronidase, beta-galactosidase, aryl sulfatases A and B) were liberated almost completely into the supernatant, and nearly all the beta-glucosidase also was liberated. It is postulated that damage to the subcellular membranes is an important component of the toxic action of sporofusarin.
...
PMID:Action of the mycotoxin of Fusarium sporotrichiella v. sporotrichioides on lysosomal membranes. 111 54

Hyperammonemia interferes with normal brain function. The effect of ammonia on free and membrane-bound lysosomal enzymes and on mucopolysaccharide metabolism was studied in cultured rat brain cells (ROC-1, hybridoma between C6-astrocytoma and oligodendrocytes). Intralysosomal ammoniagenesis was achieved from urea by endocytosed Jackbean urease followed by incubation of the cultures with urea. The intralysosomal location of urease was evidenced by the protective effects of leupeptin and urea on the stability of intracellular urease. Ammonia formed from urea resulted in an increased secretion of lysosomal arylsulfatase-A (AS-A), but not of the membrane-bound lysosomal beta-glucosidase into the culture medium, thus intralysosomal AS-A activity decreased. Lysosomal, membrane-bound beta-glucosidase activity increased, presumably due to intralysosomal proteolytic protection following an increased lysosomal pH. Intralysosomal ammoniagenesis temporarily impaired 35SO4-glycosaminoglycan degradation of prelabeled cells. The results support the hypothesis that hyperammonemic states may interfere with lysosomal functions in vivo as well in cultured cells.
...
PMID:Intralysosomal generation of ammonia from urea by endocytosed urease results in secretion of free lysosomal arylsulfatase-A and increased activity of membrane-bound beta-glucosidase in cultured brain cells. 168 84

Lymphoid cell lines from patients with infantile (type-2) and juvenile (type 3) Gaucher disease have been established by Epstein-Barr virus transformation and investigated and compared with the adult phenotype (type 1) with the view to enzymology. The enzymatic defect in glucosylceramide(GlcCer)-beta-glucosidase activity was more severe in type 2 and 3 than in type 1 cells. The mutant GlcCer-beta-glucosidase from our studied type 2 lymphoid cells was profoundly labile at pH 4.0 and 37 degrees C, whereas the residual GlcCer-beta-glucosidase from type 1 and type 3 were stable similar to the normal enzyme. In contrast to the distinct stability of the GlcCer-beta-glucosidases from the three phenotypes, the acid lability of the nonspecific membrane-bound beta-glucosidases from type 1, 2 and 3 were quite similar.
...
PMID:Acid lability of the mutated glucosylceramide-beta-glucosidase in a lymphoid cell line from type 2 Gaucher disease. 212 38

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.
...
PMID:Purification and properties of N-acetylglucosaminide alpha 1----3-fucosyltransferase from embryonal carcinoma cells. 242 30

The genetic defect in Gaucher disease consists in a deficiency of a membrane-bound lysosomal acid beta-glucosidase. Using the radiation inactivation method, we have previously reported a subunit coupling of the mutated acid beta-glucosidase from Gaucher type 1 spleen in contrast to the normal one (Maret, A., Potier, M., Salvayre, R. and Douste-Blazy, L. (1983) FEBS Lett. 160, 93-97). We have used the same method to determine the effect of detergents on subunit coupling or uncoupling of acid beta-glucosidase in normal and Gaucher spleens. The hypothesis that detergent activation of beta-glucosidase could be due to subunit association or dissociation has been tested. The radiation inactivation size of beta-glucosidase in absence of detergent was 71,000 and 135,500 for normal and Gaucher spleen, respectively, whereas the corresponding values in presence of detergent were 84,000 and 169,000. The higher values obtained in the presence of detergent are incompatible with association or dissociation of subunits but correspond to the increase generally observed for proteins irradiated in the presence of Triton X-100.
...
PMID:In vitro detergent activation of lysosomal acid beta-glucosidase in the spleen of normal and type 1 Gaucher patients is not accompanied by change in aggregation state. 250 83


1 2 3 4 Next >>

---