Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mouse mutants testicular feminization and sex reversal have been used to investigate hormone-mediated induction and repression of enzymes. Tfm/Y animals were already known to be androgen insensitive, rendering the androgen-inducible enzymes ADH and beta-glucuronidase noninducible because of an inherited deficiency of a cytosol androgen-receptor complex. The animals display female secondary sexual characteristics. Sxr/+,XX animals display male primary and secondary sexual characteristics with small testes. We demonstrate (1) that the Tfm mutation is pleiotropic, preventing repression of an androgen-repressible enzyme (ornithine aminotransferase) as well as induction of androgen-inducible enzymes, (2) that an estrogen-inducible enzyme (histidine decarboxylase) is not affected by the Tfm mutation, and (3) that Sxr/+,XX animals produce enough androgen for malelike activities of androgen-sensitive enzymes. It was also discovered that histidine decarboxylase repressed by androgen in normal animals, rather than being unaffected by it in Tfm/Y animals, is in fact induced. This unexpected phenomenon is discussed and an explanation is suggested for it.
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PMID:Effect of the mouse mutants testicular feminization and sex reversal on hormone-mediated induction and repression of enzymes. 3 63

The effects of acute and chronic administration of D-Galactosamine (GalN), Ethanol and Phenobarbital were investigated on the activities of lysosomal enzymes, i.e.; acid phosphatase, beta-glucuronidase and n-acetyl-beta-glucosaminidase, and others such as gamma-GTP and adenosine triphosphatase. The histochemical distribution of gamma-GTP in the liver was also studied on biopsy specimens from patients with chronic hepatitis, and gamma-GTP levels in the serum of patients receiving drugs inductable of hepatic microsomal enzymes. 1) After a single intraperitoneal injection of GalN, the lysosomal enzyme activities were lowered in the necrotic areas, but raised in the perinecrotic areas, the proliferative Kupffer cells and intra- and/or extra-cellular eosine bodies. 2) gamma-GTP activities in rat liver after chronic administration of GalN were markedly increased in bile canalicular membrane of periportal parenchymal cells, the epithelium of bile duct and ductules, and som inflammatory cells of portal fields. Levels of serum gamma-GTP were also elevated. On histochemical studies with biopsy specimens from patients with chronic active hepatitis showing elevated gamma-GTP activity, the activity was revealed a similar localization to GalN-treated rats. These data suggested that the increased activities might be reflected on the active stage in chronic hepatitis. 3) Chronic ethanol treatment in rats induced clearly-stained lysosomes varied in size, especially large-sized. The activities of hepatic gamma-GTP were slightly increased in the bile canalicular membrane of periportal parenchymal cells and the epithelium of proliferative bile ductules. 4) It has been shown by histochemical and biochemical techniques that hepatic gamma-GTP activity was increased after phenobarbital administration in rats. A significant rise in serum gamma-GTP was observed in patients on long-term treatment with anti-epileptic drugs. These data indicated that the increased activities of serum gamma-GTP might be accompanied with induction of hepatic microsomal drug-metabolizing enzymes.
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PMID:[Clinical and experimental histochemical studies on the activities of liver lysosomal enzymes and gamma-glutamyl transpeptidase (gamma-GTP) (author's transl)]. 3 25

Oxazepam glucuronide isolated from swine urine by previously published methods was separated into its diastereoisomers by ion-exchange chromatography on a preparative scale. Quantitative high-performance liquid chromatography was used to monitor the separation. The two isomers were obtained in analytically pure form and then characterized by elemental analysis, oxazepam content, mass spectrometry, ultraviolet spectroscopy, optical rotation and optical rotatory dispersion-circular dichroism. The latter permitted the assignment of the dextrorotatory and the levorotatory isomers to the (S)- and (R)- configurations, respectively. Rates of enzymic hydrolysis depend on the configuration of the substrate as well as on the enzyme preparation used. Rate of cleavage was highest with the (S)-(+)-glucuronide and beta-glucuronidase from Escherichia coli. This enzyme possesses the highest degree of stereoselectivity; it hydrolyzes the (S)-(+)-isomer more than 400 times faster than the (R)-(-)-form. Bovine liver glucuronidase is less stereoselective, whereas glucuronidase preparations of molluscan origin exhibit little stereoselectivity. The ready hydrolysis of one of the glucuronides by an enzyme from an intestinal microorganism may play a role in the enterohepatic circulation of oxazepam.
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PMID:Diastereoisomeric glucuronides of oxazepam. Isolation and stereoselective enzymic hydrolysis. 3 25

beta-Glucuronidase activity determined in 100 diluted bile samples from 12 rats with bile duct fistula by using phenolphthalein glucuronide as substrate incubated at 56 degrees C and pH 6 was 636 +/- 650 (mean +/- S.D.) modified Sigma units/ml. The enzyme had an optimal pH of 6.0 and was inhibited slightly by cholate by markedly by chenodeoxycholate and deoxycholate. The biliary beta-glucuronidase had, thus, low activity under normal physiologic condition because of the high pH (8.1) and high bile salt content (20 mumoles/ml) of the bile. The enzyme kinetic studies revealed that the direct bilirubin was a competitive inhibitor to phonolphthalein glucuronide for the enzyme. The affinity of the former to the enzyme was 163 times that of the latter. The studies provided a method for measuring the true activity of biliary beta-glucuronidase (Vmax) devoid of interfering factors by measuring the enzyme velocity (v) in the diluted bile with at least five different concentrations of substrate (s). The plotting of (1/v) vs. (1/s) should yield the y intercept or (1/Vmax).
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PMID:Characterization and determination of the activity of biliary beta-glucuronidase in rats. 3 79

The urinary excretion of lactate dehydrogenase, gamma-glutamyltransferase, alkaline phosphatase, arylsulphatase A, alpha-glucosidase, beta-galactosidase, trehalase, N-acetyl-beta-glucosaminidase, beta-glucuronidase, and leucine arylamidase was studied in 68 patients with biopsy-proved glomerular, 54 with interstitial renal disease and in 97 patients suffering from primary hypertension. The enzyme output of these 219 patients was compared to that of a reference population of 100 thoroughly selected healthy subjects. The highest incidence of elevated enzyme excretion was observed for N-acetyl-beta-glucosaminidase with 88% in glomerulopathies and 78% in interstitial disease, followed by beta-galactosidase. 94% of the patients with glomerular kidney disease, 90% of those with interstitial disease and about 60% of the subjects with primary benign hypertension revealed an output of at least one enzyme above upper reference limit. The highest average enzymuria occured in glomerulopathies, particularly high values in patients with the nephrotic syndrome. Application of discriminant analysis to the urinary enzyme pattern of glomerular and interstitial renal diseases resulted in an overall correct classification into the appropriate group of 89% of all patients. The discrimination between glomerular and interstitial disease was better in patients with normal renal function than in those with reduced function. Results show, that the analysis of urinary enzyme patterns may be a helpful adjunct for differential diagnosis of kidney diseases.
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PMID:Evaluation of urinary enzyme patterns in patients with kidney diseases and primary benign hypertension. 3 57

The beta-glucuronidase in homogenates of 12-day chick embryo livers catalyzed the release of glucuronic acid from 4-methylumbelliferyl-beta-D-glucuronide and from the nonreducing terminals of the hexasaccharides of chondroitin-6-SO4 and chondroitin-4-SO4 at rates of 143, 114, and 108 nmol of glucuronic acid/h/mg of protein, respectively, when assayed at pH 3.5 in 0.05 M sodium acetate buffer. During a 60-fold purification of the enzyme, the ratios of the activities on these substrates did not change. When 4-methylumbelliferyl-beta-D-glucuronide was used as substrate the enzyme was active at pH values from 3.0 to 5.5, with maximal activity between pH values 4.0 and 4.5. Concentrations of NaCl from 0.15 to 0.3 M inhibited the activity at low pH values but activated the enzyme between pH 4.0 and 5.5. The enzyme was active on the chondroitin-6-SO4 hexasaccharide from pH 3.0 to 5.5, with a broad optimum between 3.0 and 4.5. NaCl inhibited the activity on the oligosaccharide substrate at all pH values. Eadie-Scatchard plots of rates of 4-methylumbelliferyl-beta-D-glucuronide hydrolysis at substrate concentrations ranging from 2 to 1000 microM showed multiple kinetic forms of the enzyme, a form with a Km of approximately 11 microM, and a second form with a Km of approximately 225 microM. The pH optimum of the low Km form was 3.5 to 4.0; that of the high Km form was pH 4.5. NaCl inhibited the activity of the low Km form, but activated the high Km form of the enzyme. Chondroitin SO4 oligosaccharides competed with 4-methylumbelliferyl-beta-D-glucuronide for the low Km form of the enzyme but had little effect on the hydrolysis of 4-methylumbelliferyl-beta-D-glucuronide by the high Km form of the enzyme. The activities of the beta-glucuronidase on tetra-, hexa-, octa-, and decasaccharides of chondroitin-6-SO4 and chondroitin-4-SO4, measured using a new assay procedure which can detect the formation of 1 nmol of product, were similar, although rates were somewhat lower for the higher oligosaccharides. With the exception of the chondroitin-4-SO4 tetrasaccharide, all of the oligosaccharide substrates saturated the enzyme at concentrations of 20 to 30 microM, indicating Km values of less than 10 to 15 microM for the oligosaccharides. Highly purified beta-glcuronidases from human placenta and from rat preputial gland also showed multiple kinetic forms when assayed using 4-methylumbelliferyl-beta-D-glucuronide as substrate.
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PMID:Chick embryo liver beta-glucuronidase. Comparison of activity on natural and artificial substrates. 3

Microsomal fraction contains the whole of hepatic UDP-glucuronyltransferase as well as part of beta-glucuronidase. The activities of the two enzymes were assayed under identical conditions using untreated male rat liver microsomes at pH 7.5. In a 30-min incubation with p-nitrophenol and UPD-glucuronic acid, a net glucuronide formation of 0.010 mumol.min-1.g.liver-1 was measured. In the presence of saccharolactone at concentrations selectively blocking beta-glucuronidase, the glucuronidation rate was 0.015 mumol.min-1.g.liver-1. Using the kinetic parameters of beta-glucuronidase (Km = 0.06 mmol/l p-nitrophenylglucuronide, Vm = 0.075 mumol pNP formed.h-1.g.liver-1) determined in the absence of UDP-glucuronic acid, to correct for the beta-glucuronidase's interference on the glucuronidation process, a glucuronide formation of 0.011 mumol.min-1.g.liver-1 was calculated.
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PMID:Interference of UDP-glucuronyltransferase and beta-glucuronidase activity in rat liver microsomes at pH 7.5 with p-nitrophenol and p-nitrophenylglucuronide as substrates. 3 49

In order to investigate the origin of unconjugated bilirubin in bile, beta-glucuronidase activity in rat and human bile was determined at various pH. beta-Glucuronidase in rat and human bile had their optimum pH at 5.5 when phenolphthalein glucuronide and delta 1-azopigment were used as substrate, and at 6.0 when bile itself was incubated. In human and rat bile the hydrolysis was suppressed to a minimum at each physiologic pH. However, human bile shows remarkable hydrolysis in alkaline pH (7.5--8.0). On the other hand, when delta 1-azopigment was incubated in various buffers, several per cent of delta 1-azopigment were hydrolyzed non-enzymatically in neutral to alkaline pH. Thus, it was suggested that enzymatic and nonenzymatic hydrolysis contributes to the existence of unconjugated bilirubin in bile.
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PMID:The origins of unconjugated bilirubin in bile. 3 65

Twelve acid hydrolases, 4 near-neutral hydrolases, and alkaline phosphatase were demonstrated in 0.34 M sucrose homogenates of Trypanosoma cruzi strain Y: p-nitrophenylphosphatase and alpha-naphthylphosphatase, with optimum pH at approximately 6.0; alpha=ga;actpsodase. beta=ga;actpsodase. beta=g;icpsodase, N-acetyl-beta-glucosaminidase, cathepsin A and peptidase I and III, with optimum pH between 5.0 and 6.0; and arylsulfatase, cathepsin D, alpha-arabinase and alpha-mannosidase with optimum pH at approximately 4.0. alpha-Glucosidase, glucose-6-phosphatase and peptidase II had optimum pH at approximately 7.0. beta-Glycerophosphatase had a broad pH-activity curve from 4,0 to 7.4, with maximum activity at pH 7.0. The main kinetic characteristics of these enzymes and their quantitative assay methods were studied. No activity was detected for alpha-fucosidase, beta-xylosidase, beta-glucuronidase, elaidate esterase, acid lipase, and alkaline phosphodiesterase.
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PMID:Acid and neutral hydrolases in Trypanosoma cruzi. Characterization and assay. 4 19

Livers from either control or spironolactone-treated rats were perfused for a 90-min period with 30% rat blood and 3H-digitoxin. At several time periods throughout perfusation, bile was collected and a sample of blood was removed from the perfusate. Extractions were performed on both blood and bile to determine amount of polar and nonpolar metabolites at 60 min. Polar metabolites were cleaved with beta-glucuronidase and high-pressure liquid chromatography was used to separate the resultant nonpolar metabolites from blood and bile cleaved with beta-glucuronidase. Biliary excretion and perfusate disappearance of 3H-digitoxin were significantly increased in livers taken from spironolactone-pretreated animals. Both polar and nonpolar metabolites in bile were significantly increased in pretreated animals. The majority of polar metabolites produced by livers from both treated and nontreated animals were readily cleaved with beta-glucuronidase. Both biliary excretion and metabolic pattern, obtained from these studies in an isolated perfused rat liver, mimic those seen in the intact rat. Thus, the isolated perfused rat liver can be used as a model for in vivo studies of cardiac glycoside metabolism.
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PMID:Metabolism of digitoxin in the isolated perfused rat liver. Effect of spironolactone pretreatment. 4 Jul 66


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