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)

Histological studies showed that the administration of p-nitrophenylarsonic acid to rats resulted in renal tubular necrosis. The nephrotoxin was administered intraperitoneally and doses greater than 30 mg/kg were found to be fatal. The severity of the renal lesion depended on the amount of the nephrotoxin used. Elevated serum urea levels, urinary protein and volume were recorded over an 8-day period following the injection of the nephrotoxin. These changes were paralleled by an increase in the activity of lactate dehydrogenase, acid and alkaline phosphatase, N-acetyl-beta-glucosaminidase and beta-glucosidase in the urine. beta-Glycosidase activities increased in kidney homogenates, immediately after the injection of the nephrotoxin, but this eventually fell to well below the normal range. Subcellular fractions were prepared from sucrose homogenates by differential centrifugation and beta-glycosidases and cytochrome oxidase were used as enzyme markers. Only minor changes in the activity of cytochrome oxidase activity resulted from the administration of p-nitrophenylarsonic acid. One of the earliest indications of renal damage was a decrease in lysosomal latency. The activities of the lysosomal and soluble enzymes were elevated above normal during the first two days after the injection of p-nitrophenylarsonic acid, but they fell to values, significantly lower than normal, on the third day. The isoenzymic forms of beta-galactosidase, beta-glucosidase and N-acetyl-beta-glucosaminidase in normal and damaged kidneys were studied, using starch gel electrophoresis. The activities of both the lysosomal and the soluble forms of these enzymes decreased following the injection of the nephrotoxin, confirming the results obtained with whole homogenates. The relationship between the changes in renal enzyme activity and urinary enzyme excretion during the nephrotoxic process is discussed.
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PMID:Studies on the nephrotoxicity of p-nitrophenylarsonic acid: changes in rat kidney and urinary enzyme activities following the administration of p-nitrophenylarsonic acid. 21 43

N-Acetyl-beta-glucosaminidase, beta-galactosidase, beta-glucosidase, acid and alkaline phosphatase were monitored in urine kidney homogenates and serum of rats with papillary damage induced with ethyleneimine. Serum urea levels, total protein in the urine and urine volume were monitored throughout the study. Histological studies showed that the injection of ethyleneimine caused immediate papillary necrosis, followed later by secondary cortical involvement. Minor papillary necrosis induced by a low dose (0.5 mul/kg) of ethyleneimine was characterised by a rise in urinary N-acetyl-beta-glucosaminidase activity which was followed later by an increase in the activity of the other enzymes monitored. More severe papillary necrosis induced with a higher dose of ethyleneimine (5.0 mul/kg) resulted in an immediate rise in the activities of all the urinary enzymes which then decreased only to rise again when cortical involvement occurred. Serum urea was unaltered but urine volume and protein were increased coincidentally with the urinary enzyme activities. The value of the assay of urinary enzymes in distinguishing papillary from glomerular and tubular damage is assessed. The possible relevance of the ethyleneimine model to the etiology of papillary nephropathy is discussed.
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PMID:Urinary enzyme excretion during renal papillary necrosis induced in rats with ethyleneimine. 120 12

Stability of C1- and C2-cellulases, CX-exo- and CX-endoglucanases and beta-glucosidase of Aspergillus awamori was studied as affected by monoatomic aliphatic alcohols --methanol, ethanol, propanol and isopropanol; bi- and triatomic alcohols - ethylene glycol and glycerol, urea as well as detergents of dodecyl sulphate and sodium nonilate. The mentioned enzymes are established to manifest the highest activity in 40-60% glycerol. It is also shown that their stability is changed differently under the effect of other alcohols, urea and detergents. The latter testifies to the fact that the studied enzymes are nonidentical, in particular, they differ between themselves by a ratio of intramolecular forces which stabilize their macrostructure.
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PMID:[Role of intramolecular bonds in stability of certain enzymes of the cellulolytic complex]. 125 59

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.
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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

A facile isolation of beta-glucosidase (EC 3.2.1.21) from Escherichia coli containing the recombinant plasmid pNZ1001 carrying a beta-glucosidase gene from the extremely thermophilic anaerobic bacterium Tp8 is reported. The enzyme was purified to homogeneity by anion-exchange chromatography and steric exclusion HPLC following thermal denaturation/precipitation of heat-labile E. coli proteins. The enzyme had a broad specificity for beta-D-glucosides, galactosides, fucosides, and xylosides. Action on aryl-beta-D-glycosides of glucose, galactose, and fucose was characterized by low Km and high Kcat/Km values compared with disaccharide substrates for which specificity decreased in the order laminaribiose, sophorose, cellobiose, beta-gentiobiose, lactose. Galactono-1-4-lactone, glucono-1-5-lactone, and 1-O-methyl-beta-D-glucose were competitive inhibitors with Ki values of 1.6, 0.09, and 17.5 mM, respectively. The enzyme was remarkably stable to detergents, urea, and organic solvents. Thermostability was greatest at the pH activity optimum (pH 6.0-6.5) and half-life (t1/2) values were 11 min at 90 degrees C, 105 min at 85 degrees C, and 900 min at 80 degrees C. Activity was destabilized by Sr2+, Co2+, Ca2+, Mg2+, and Mn2+, but t1/2 increased in the presence of substrates or competitive inhibitors. Activation energy, Ea, was 54.3 kJ.mol-1. A free thiol group(s) was required for full activity, this being rapidly lost in the presence of Hg2+ or N-ethyl maleimide.
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PMID:Stability and substrate specificity of a beta-glucosidase from the thermophilic bacterium Tp8 cloned into Escherichia coli. 312 75

Homogenates of Giardia lamblia trophozoites exhibited the following hydrolase activities: acid phosphatase (EC 3.1.3.2), proteinase (EC 3.1.4) with urea-denatured hemoglobin and N-benzoyl-DL-arginine-2-naphthylamide as substrates, deoxyribonuclease (EC 3.1.4.5), and ribonuclease (EC 2.7.7.16). beta-N-Acetylglucosaminidase (EC 3.2.1.30), beta-galactosidase (EC 3.2.1.23), beta-glucuronidase (EC 3.2.1.31), alpha-D-glucosidase (EC 3.2.1.20), beta-D-glucosidase (EC 3.2.1.21), and beta-D-xylosidase (EC 3.2.1.37) activities were below the level of detection. Differential and isopycnic centrifugation of homogenates demonstrated that giardial hydrolases were localized in a single-particle population sedimenting at 7200g for 30 min. The particles had a buoyant density in sucrose of 1.15 and exhibited latency. Latency was completely destroyed by Triton X-100 or 15 cycles of freezing and thawing. After centrifugation of Triton- or freeze-thaw-treated particle fractions, the hydrolase activities, though no longer latent, were still sedimentable suggesting tight binding to the organelle membrane. Latency was destroyed simultaneously for all hydrolases, in direct proportion to the amount of Triton added to a particle preparation or to the number of times a particle preparation was subjected to freezing and thawing. These results support the suggestion that the hydrolases of G. lamblia trophozoites are localized in a single-particle population of lysosome-like organelles.
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PMID:Giardia lamblia: localization of hydrolase activities in lysosome-like organelles of trophozoites. 327 50

Intracellular beta-glucosidase was extracted from the mycelium of Th. aurantiacus, concentrated by DEAE-cellulose treatment, separated from alpha-glucosidase by hydroxylapatite chromatography and purified to electrophoretic homogeneity. Optimally active at 75 degrees C and pH 4.2, beta-glucosidase displayed complex kinetics with p-nitrophenyl-beta-glucoside which inhibited the enzyme at concentrations greater than 0.5 mM. With cellobiose the kinetics were practically hyperbolic at 70 degrees C (Hill coefficient nH = 1.09 and Km = 0.83 mM), but faint inhibition was observed at 50 degrees C. beta-glucosidase shares with alpha-glucosidase a high number of physicochemical properties: with similar aminoacid composition, very close isoelectric point (4.5 and 4.2), high molecular weight in the native state (175,000 and 140,000), the two enzymes showed the same behaviour on DEAE-cellulose, were equally stable at high temperature and were dissociated by 6 M urea to still active proteins. Furthermore, the carbohydrate contents of beta-glucosidase (17.6%) is not far from that previously determined for some forms of alpha-glucosidase (14-16%).
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PMID:Comparative study of glucosidases from the thermophilic fungus Thermoascus aurantiacus Miehe. Purification and characterization of intracellular beta-glucosidase. 393 99

This enzyme shows beta-D-glucosidase, beta-D-fucosidase and beta-D-galactosidase activities, all associated in a single peak in Sephadex G-200, DEAE-cellulose, concanavalin A-Sepharose chromatographies, and in high resolution isoelectric focusing (pI 4.56), having the optimal pH in the range 4.5-5.5. The enzyme is very stable under different conditions: (i) at pH in the range 5.5-7.0; (ii) in successive freezing-thawing cycles; (iii) at 4 degrees C; (iv) after exhaustive ultrasonic treatment. It is not stable beyond 40 degrees C, and in the presence of urea, Triton X-100, SDS or mercaptoethanol. HgCl2, KCN, Tris, maltose and the lactones were inhibitors of the enzyme. With glucose, fucose and galactose the inhibition is competitive. In addition, a transglycosylation mechanism seems to occur. The kinetic studies suggest a substrate-activation model and the presence of two primary active sites: fuco-gluco and galacto.
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PMID:Characterization and kinetics of beta-D-gluco/fuco/galactosidase from sheep liver. 641 26

A pancreas cancer-associated antigen (PCAA) was identified and isolated from ascites fluid of human pancreatic cancer. Purified PCAA was homogeneous as determined by polyacrylamide gel electrophoresis. PCAA was a glycoprotein with a molecular weight of approximately 1,000,000 and consisted of 20% carbohydrates and 80% peptides, had an isoelectric point of 4.7, and migrated to alpha 2-beta region. It possessed a sedimentation coefficient of 14S and appeared to be a fibrous or fibroglobular protein. Immunoreactivity of PCAA was sensitive to proteolytic enzymes, perchloric acid, KSCN, glycine-HCl at pH 2.5, urea and lithium diiodosalicylate; and insensitive to neuraminidase or beta-glucosidase. Immunohistochemical technique revealed that PCAA was located in the cytoplasm of ductal epithelial cells of malignant pancreas. Using heteroantiserum raised against purified PCAA, horseradish peroxidase and CNBr-activated Sepharose 4B, an enzyme-immunoassay (EIA) for circulating PCAA has been developed. From a group of 40 healthy blood donors, an upper limit of 16.2 micrograms of PCAA/ml of serum has been tentatively determined. An elevated PCAA was shown in 67% (29/43) of patients with pancreas cancer, as well as in 30% (11/36) of lung cancer patients, 27% (10/37) of colonic cancer patients, and in 16% (6/36) of breast cancer patients. The reactive antigen in sera of these cancers was shown to be immunologically identical. PCAA also was detected in extracts of various human tissues, particularly pancreatic tumors, colonic tumors, and in a normal colon. Further, PCAA exhibited heterogeneity in molecular weight, isoelectric point, and electrophoretic mobility.
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PMID:Isolation, characterization and clinical evaluation of a pancreas cancer-associated antigen. 702 47

Three glucosyl-phenolic hydroxamates, 4-O-(beta-D-glucopyranosyl) benzohydroxamic acid, 4-O-(beta-D-glucopyranosyl)hippuric hydroxamic acid, and 3-[4-O-(beta-D-glucopyranosyl)phenyl]propionohydroxamic acid (Glc-PPHA), were hydrolyzed to their corresponding aglycones by beta-glucosidase of intestinal flora of rat without any major adverse hydrolysis in vitro. Inhibitory potency of these glucosyl-hydroxamates on urease was recovered to the same extent as that of the corresponding aglycone hydroxamates by preincubation for 2h with rat intestinal flora. p-Hydroxyphenylpropionohydroxamic acid inhibited noncompetitively jack-bean urease activity and its glucose-ligated form, Glc-PPHA inhibited it competitively. A single oral dose of Glc-PPHA tended to inhibit urease activity in proximal colon contents of rat at 6 h after administration (p = 0.06). After 14C-urea was orally administered to rat, 14CO2 was collected for to measure the ureolysis in vivo. Expired 14CO2 was limited to 40% by a single oral dose of Glc-PPHA during 6 h, and 75% of intestinal ureolysis was repressed during the first 1 h in the breath test.
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PMID:Inhibitory effect of beta-glucosyl-phenolic hydroxamic acids against urease in the presence of microfloral beta-glucosidase. 774 85


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