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

Myocardial ischemia was produced for 2 hours by coronary ligation in 11 dogs pretreated with methylprednisolone (MP, 30 mg/kg). Myocardial blood flow (MBF) was measured with microspheres (15 micrometer) in each tissue sample used for enzymatic analysis. Homogenates of these tissue samples were separated by ultracentrifugation into lysosome-rich and microsomal fractions and were analyzed for N-acetyl-beta-glusosaminidase (NAGA), beta-glucuronidase (beta-gluc), rotenone-insensitive-NADH-cytochrome c reductase (RINCR), and cytochrome oxidase. The enzymatic data from centrifugal fractions were grouped according to MBF values for statistical analysis of inter-group effects of ischemia. Significant losses (P less than 0.001) of NAGA and beta-gluc were seen in all MP-treated lysosome-rich particulate fractions that were isolated from zones demonstrating MBF values less than 25% of control (L-ischemia). Similar significant losses (P less than 0.001) of RINCR were seen in microsomal fractions from L-ischemia zones. Samples with MBF values greater than 25% but less than 75% of control (M-ischemia) also demonstrated significant decreases of lysosomal and microsomal enzymatic activity in specific fractions. When the data of the above MP-treated group were compared with the untreated control group, no significant intergroup effects of treatment with MP were observed. In addition, enzymatic data (NAGA, RINCR) were normalized prior to performing linear regression analyses; percent loss of particulate enzymatic activity was plotted against percent decrease in MBF. The effects of 2 hours of ischemia on the above biochemical parameters were comparable between untreated and MP-treated groups. Finally, when myocardial samples were grouped according to similar levels of MBF, statistical analysis using the general linear models procedure revealed no beneficial effect of MP treatment on changes in lysosomal hydrolases, microsomal RINCR, or latency of lysosomes.
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PMID:Lack of effect of methylprednisolone on lysosomal and microsomal enzymes after two hours of well-defined canine myocardial ischemia. 21 3

Isoelectric focusing was used to investigate the multiple forms of acid phosphatase, arylsulfatase, beta-glucuronidase, beta-galactosidase and beta-N-acetylhexosaminidase in the following, previously characterized subcellular fractions from rat kidney: a special rough microsomal fraction, enriched up to 9-fold over the homogenate in acid hydrolases; a smooth microsomal fraction; a Golgi membrane fraction enriched about 2.5-fold in acid hydrolases and 10- to 20-fold in several glycosyl transferases; and a lysosomal fraction enriched up to 25-fold in acid hydrolases. The electro-focusing behavior of the hydrolases in these fractions was markedly sensitive to the autolytic changes that occur under acidic conditions, even at 4 degrees C. Autolysis was minimized by extracting fractions in an alkaline medium (0.2% Triton X-100, 0.1 M sodium glycinate buffer, pH 10, 0.1 % p-nitrophenyloxamic acid) and adding p-nitrophenyloxamic acid (0.1 %), AN INHIBITOR OF LYSOSOMAL NEURAMINIDASE AND cathepsin D, to the pH gradient. The enzymes in the lysosomal fraction displayed a characteristic bimodal or trimodal distribution. Arylsulfatase, beta-glucuronidase and beta-N-acetylhexosaminidase occurred in an acidic form with an isoelectric point of 4.4, and a basic form with an isoelectric point of 6.2, 6.7 and 8.0, respectively. Acid phosphatase and beta-galactosidase occurred in an acidic, intermediate and basic form with isoelectric points of about 4. 1, 5.6 and 7.4, respectively. In the special rough microsomal fraction these enzymes were mostly in a basic form with isoelectric points between 7.5 and 9; these were 1-2 units higher than the corresponding basic forms in the lysosomal fraction. Treatment of extracts of the rough microsomal fraction with bacterial neuraminidase raised the isoelectric points of all five hydrolases by 1-2.5 units, indicating the presence of some N-acetylneuraminic acid residues in these basic glycoenzymes. The hydrolases in the Golgi fraction were largely in an acidic form with isoelectric points similar to or lower than those of the corresponding acidic components in the lysosomal fraction. The hydrolases in the smooth microsomal fraction showed isoelectric-focusing patterns intermediate between those in the rough microsomal and the Golgi fractions. These findings support the following scheme for the synthesis, transport and packaging of the lysosomal enzymes. Each hydrolase is synthesized in a restricted portion of the r
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PMID:Changes in electronegativity of lysosomal hydrolases during intracellular transport. An isoelectric-focusing study in subcellular fractions of rat kidney. 23 56

Highly purified rat liver microsomal or lysosomal beta-glucuronidase (beta-D-glucuronide glucuronosohydrolase, EC 3.2.1.31) catalyzes the specific transfer of glucuronly residues from phenyl-beta-D-[U-14C]glucuronide to acceptor sugars. Specificity requirements of acceptor sugars are found to be: pyranose structure, 4C1-conformation and equatorial position of C2 and C3 hydroxyl groups or pyranose structure, 1C4-conformation and equatorial position of C3 and C4 hydroxyl groups. The acceptor capacities of 30 monosaccharides and glycosides including di- and tri- saccharides conform to this prinicple. The specificity of the beta-glucuronidase catalyzed glucuronyl transfer is proved by the exclusive formation of beta-glucuronly (1--3)glycosidic linkages. Glucuronly transfer rates increase with increasing donor substrate and increasing acceptor sugar concentration. In the presence of 1 M acceptor sugar the ratio of the transfer rate to the rate of enzymatic hydrolysis is about 2:1. An 'acceptor substrate binding site' on the surface of the beta-glucuronidase molecule which brings the C3 hydroxyl function of the acceptor sugar close enough to the C1 atom of the glucuronyl residue, is postulated.
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PMID:Acceptor-specific glucuronyl transfer catalyzed by beta-glucuronidase. 45 23

Pentachlorophenol has earlier been shown to be metabolized in mammals to tetrachloro-p-hydroquinone. The metabolite possesses pronounced inhibitory activity on bacterial beta-glucuronidase but not on beta-glucuronidase from liver. Indirect evidence for the occurrence of both pentachlorophenol and tetrachloro-p-hydroquinone as conjugates with glucuronic acid in the urine from pentachlorophenol-treated rats is now presented. Bovine liver beta-glucuronidase has been utlizied to split the conjugates present. The in vivo metabolism of pentachlorophenol has also been studied in rats treated with phenobarbital and beta-diethylaminoethylidiphenyl propylacetate (SKF 525-A). In vitro metabolism has been studied using liver microsomes from rats pretreated with pehnobarbital. Quantitative analysis of the compounds occurring in extracts of urine or extracts from the microsomal incubates was performed by means of mass fragmentography. Pretreatment with phenobarbital increased the metabolism of pentachlorophenol to tetrachloro-p-hydroquinone both in vivo and in vitro. SKF 525-A, however, inhibited the metabolism in vitro but enhanced the metabolism in vivo when given less frequently than every 6th h. Dechlorination of pentachlorophenol is mediated by microsomal enzymes that can be induced by phenobarbital. SKF 525-A does not inhibit the dechlorination in vivo but does so in vitro.
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PMID:Metabolism of pentachlorophenol in vivo and in vitro. 58 Mar 75

The activities of certain drug metabolizing enzymes have been measured in liver and kidney slice preparations from domesticated birds. Aminopyrine demethylase activity was significantly lower in liver slices from the duck (Aylesbury X Pekin, Khaki-Campbell) than from the rat (Wistar), and in the Aylesbury X Pekin duck lower than in the turkey (Triple 6 FLX), chicken (Brown Leghorn, Rhode Island Red X Light Sussex) and goose (Emden X Doulouse). The microsomal cytochrome P-450 was lower in duck liver (Aylesbury X Pekin) than in rat liver, and the aniline hydroxylase and aminopyrine demethylase activities in a 10,000 g supernatant fraction of liver were lower in duck preparations (Aylesbury X Pekin, Khaki-Campbell) than rat preparations. These observations suggest that the duck is likely to be susceptible to drugs which are metabolized by the cytochrome P-450 containing mono-oxygenases. UDP-Glucuronyl transferase activity was not detectable in liver and kidney slices from two mature geese. This observation was not the outcome of a deficiency of UDP-glucuronic acid, rapid breakdown of glucuronide by beta-glucuronidase or the presence of a substance inhibitory to UDP-glucuronyl transferase. Liver slices from geese, ducks (Aylesbury X Pekin) and chickens contained low UDP-glucuronyl transferase and high sulphate conjugation enzyme activities, whereas the reverse was found in Khaki-Campbell ducks. The activities of UDP-glucuronyl transferase and the sulphate conjugation enzymes were both relatively high in liver slices from the turkey and rat. The kidney contained lower enzyme activities than the liver except in the duck (Aylesbury X Pekin), in which low activities of aminopyrine demethylase and UDP-glucuronyl transferase were present in slices of both organs. In liver slices from chickens and geese the activities of aminopyrine demethylase and the sulphate conjugation enzymes were similar in mature and immature birds, and the activity of UDP-glucuronyl transferase was considerably higher in chicks and goslings than in mature birds of the same species. In the chick the activities of aminopyrine demethylase, UDP-glucuronyl transferase and the sulphate conjugation enzymes were higher in the duodenum than the remainder of the alimentary tract. The activities of these enzymes in pieces of duodenum were as high as those in slices of liver. The inclusion of sulphate in the incubation medium produced a significant increase in the synthesis of p-nitrophenyl sulphate in liver slices and not kidney slices except those from the duck. The kidney slices seemed to produce sufficient sulphate for the reaction of the sulphate conjugation enzymes to proceed at the maximum rate, but the liver slices did not do so.
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PMID:Activities of mixed function oxidases, UDP-glucuronyl transferase and sulphate conjugation enzymes in galliformes and anseriformes. 81 57

1. Polysaccharide in a heparin-producing mouse mastocytoma was pulse-labelled in vivo with [35S] sulphate, and after various periods of time was isolated from subcellular fractions. Such fractions were recovered from tissue homogenates by consecutive centrifugations at 1000g for 10min, 20000g for 20min and 100000g for 1h. Initially the 35S-labelled polysaccharide formed occurred principally in the second centrifugal fraction (20000g precipitate), with small amounts in the first (granular) and third (microsomal) fractions. Analysis for glycosyltransferase activity confirmed that glycosaminoglycans were formed chiefly in particles sedimenting at 20000g. Molecules of this newly synthesized polysaccharide were considerably larger than those of commercially available heparin, as judged from gel chromatography. 2. Within the first hour after injection of [35S]sulphate, most of the labelled polysaccharide was redistributed from the second to the first centrifugal fraction. During, and possibly also after, this shift, the macromolecular polysaccharide was degraded, ultimately to the size of commercial heparin. The degradation process appeared complete 6h after injection of [35S]sulphate. 3. Particulate subcellular fractions were incubated with macromolecular [35S]heparin and the products were analysed by gel chromatography. Significant degradation of the substrate occurred only with the second centrifugal fraction. Further characterization of this fraction, by density-gradient centrifugation in iso-osmotic colloidal silica, revealed a single visible band of particles, at approximately the same density at lysosomes. This band contained all the beta-glucuronidase, 35S-labelled endogenous polysacchride and heparin-degrading enzyme present in the second fraction.
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PMID:Metabolism of macromolecular heparin in mouse neoplastic mast cells. 82 71

Glucuronidase present in lysosomes of mouse liver occurs as the free tetramer, whereas glucuronidase present in endoplasmic reticulum occurs in macromolecular complexes containing one to four molecules of the protein egasyn. Earlier genetic and biochemical studies suggest that these complexes, or M forms, function to stabilize the membrane binding of glucoronidase. The detergent Triton X-100 extracts glucuronidase-egasyn complexes intact and they dissociate in the presence of the detergent deoxycholate or upon heating. We have now purfied egasyn by releasing it from antiglucuronidase immunoprecipitates of M forms under relatively mild conditions, such as treatment with deoxycholate or heating at 50 degrees. Isolated egasyn is a glycoprotein of molecular weight about 64,000 and is not unusually hydrophobic in amino acid composition. Monospecific antibody to egasyn was raised. This antibody showed no cross-reactivity with purified beta-glucuronidase and antibody to glucuronidase failed to react with purified egasyn; however, both antibodies bound to egasyn-glucuronidase complexes. A procedure for the radioimmunoassay of egasyn was developed utilizing egasyn labeled with iodine 125. Most of the antigenic sites of egasyn in homogenates of normal liver are masked after extraction with Triton X-100 and only become immunoreactive after exposure to deoxycholate. After unmasking, mouse liver proved to contain about 56 mug of egasyn/g, nearly all of which is localized to the microsomal fraction. Of this total only about 10% was complexed with glucuronidase, suggesting theat the bulk of the egasyn present may be complexed with other proteins. Mice of the inbred strain YBR, which carry the EgO mutation resulting in the absence of microsomal glucuronidase, lacked immunoreactive egasyn, suggesting that the primary defect in this strain lies in the unavailabililty of agasyn to form complexes. There is now considerable evidence in support of the concept that the microsomal forms of glucuronidase exist in membranes complexed with egasyn and that formation of these complexes is required for maintenance of glucuronidase in membranes. Egasyn may represent one of a class of membrane anchor proteins that each stabilize the membrane binding of a charcteristic set of proteins.
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PMID:Isolation, characterization, and radioimmunoassay of murine egasyn, a protein stabilizing glucuronidase membrane binding. 82 34

A method for the isolation of plasma membranes from an experimental murine ependymoblastoma is described. In this procedure, 5'-nucleotidase was used as the plasma membrane marker, since cytochemical methods demonstrated that the enzyme was present on this subcellular structure only. The final plasma membrane preparation showed a 15-fold enrichment in 5'-nucleotidase activity and a 17-fold enrichment in the activity of phosphodiesterase I, another plasma membrane marker. The specific activity of beta-glucuronidase (lysosomal enzyme) was twice that of the whole homogenate, the specific activity of arylesterase (microsomal enzyme) was similar to that of the whole homogenate and succinate dehydrogenase (mitochondrial marker) was not detected. Electron microscopy of this fraction showed vesicles on which 5'-nucleotidase activity could be demonstrated. The subcellular distribution of [3H]amphotericin B per mg of protein was similar in the plasma membrane preparation and in the whole homogenate. It is concluded that, in ependymoblastoma, amphotericin B shows no selective affinity for the plasma membrane.
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PMID:Isolation of plasma membranes from murine ependymoblastoma and subcellular distribution of amphotericin B in this tumor. 85 31

Mouse beta-glucuronidase has a dual intracellular localization, being present in both endoplasmic reticulum and lysosomes of several tissues. Previous studies demonstrated that the protein egasyn is complexed with microsomal but not lysosomal glucuronidase and that a mutant lacking egasyn is deficient in microsomal, but not lysosomal, glucuronidase. By means of a recently developed radioimmunoassay for egasyn, the relationship between microsomal glucuronidase levels and egasyn levels has been examined in various adult tissues, during postnatal development in liver, and after androgen induction of glucuronidase in kidney. The results indicate that the relative availability of egasyn determines the balance between glucuronidase incorporation into membranes and that into lysosomes.
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PMID:Relationships between levels of membrane-bound glucuronidase and the associated protein egasyn in mouse tissues. 87 97

The induced secretion of rat liver microsomal-beta-glucuronidase into serum is, unlike other proteins secreted from liver, not dependent upon an intact microtubule apparatus.
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PMID:Demonstration of microtubule independent protein secretion from rat liver. 92 10


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