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 histrochemistry of the adrenal glands was studied in four adult male marmosets (two Callithrix jacchus and two Callithrix penicillata). It was impossible to demonstrate any reactivity to UDPG-GT, ADH, alanyl aminopeptidase, leucine aminopeptidase, xilitol (NAD-dependent) dehydrogenase, beta-glucuronidase and aryl-sulfatase in these glands. Total phosphorylase was found in scattered cells of the glomerulosa and adjacent outer fasciculata of one C. penicillata. The dehydrogenases (LDH, G-6-PDH,6-PGDH, NADPH2-TR,ICDH,SDH,NADH2-TR, alpha-GPDH, beta-OHBDH) as well as the hydrolases (except alkaline phosphatase, ATPase, and acetylcholinesterase) showed a stonger reactivity in the cortical part. Some hydrolases (naphthol acetate esterase, acid phosphatase) and cytochrome oxidase were less reactive in the zona glomerulosa, where the dehydrogenases were more abundant. The outer fasciculata and the reticularis also showed a strong dehydrogenase reactivity.
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PMID:Histochemical studies on the adrenal glands of the marmosets (Callithrix jacchus and Callithrix penicillata). 0 44

Some important enzymes concerned with the biosynthesis of the precursors of glycosaminoglycans (gg), degradation of gg and biological sulphation have been studied in rats fed an atherogenic diet. L-Glutamine-D-fructose-6-phosphate amino-transferase and glucosamine-6-phosphate-N-acetylase--2 enzymes concerned with the biosynthesis of hexosamine precursors of gg--decreased in the liver in rats fed the atherogenic diet. UDPG pyrophosphorylase, UDPG dehydrogenase and UDPG glucuronic acid-5'-epimerase, which are concerned with the biosynthesis of the uronic precursors of gg, also decreased in the liver in the diet-fed rats. The activities of some of the enzymes concerned with degradation of gg-hyaluronidase, beta-glucuronidase beta-hexosaminidase, cathepsin and aryl sulphatase--increased both in the liver and aorta. The hepatic concentration of PAPS significantly decreased in the diet-fed rats. The sulphate-activating system, which includes ATP sulphurylase, APS kinase and sulphotransferase, also decreased. Thus the overall picture is one of decreased synthesis of gg and their increased degradation in the atheromatous rats.
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PMID:Metabolism of glycosaminoglycans in atheromatous rats. Enzymes concerned with synthesis, degradation and sulphation of glycosaminoglycans. 12 76

The histochemistry of the hepatic parenchymal cells was studied in four Callithrix jacchus. A large amount of glycogen was noted throughout the lobules while the UDPG-GT and the phosphorylases were found unevenly distributed by the hepatic strands with different degrees of reactivity. Near the central vein one of the livers showed PAS-positive nuclear corpuscles that were more conspicuous in the hepatic cells with a larger amount of cytoplasmic glycogen and weaker UDPG-GT and phosphorylase reactivities. G-6PA (in a larger amount) and LDH (in a moderate amount) were found evenly distributed in the hepatic strands. F-1-6PA was seen sometimes with a stronger reactivity at the peripheral part of the lobules. The enzymes of the pentose shunt (G-6PDH, 6-PGDH and NADPH-2-TR) reacted strongly and as a rule evenly distributed near the hepatic lobules. Occasionally they reacted more intensely in the row of hepatic cells disposed just around the central vein. Cytochrome oxidase showed a very faint reaction. Cis-aconitase and ICDH were weak or moderate. NADH-2-TR more than SDH more than MDH were seen frequently diffused near the hepatic strands. SDH and MDH in some instances showed a stronger reactivity in the row or group of hepatic cells around the central vein. ATPase at pH 6.3 was negative in the marmoset liver; ATPase at pH 7.4 was mainly found in the wall of the portal area vessels; ATPase at pH 8.5 showed a stronger reactivity in the cytoplasm of the hepatic cells and ATPase at pH 9.4 was more abundant in the bile capillaries. The reactivity of the lipid metabolism enzymes was moderate with regard to alpha-GPDH or negligible with regard to beta-OHBDH. Acid phosphatase showed a stronger reaction, but almost limited to the Kupffer cells. The hepatic cells showed only a moderate amount of RNA. Some enzymes of the protein metabolism, such as GDH and leucine aminopeptidase showed a stronger reactivity while some others, such as alanyl aminopeptidase and MAO, were seen diffused near the hepatic lobules in a small amount. Enzymes of the mucopolysaccharide metabolism were not found at all (beta-glucuronidase) or showed only a weak reactivity, such as xylitol dehydrogenase.
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PMID:Histochemical data on the liver of the marmoset (Callithrix jacchus). 16 44

The liver cells of 8 rabbits fed for 12 to 16 weeks with a cholesterol diet showed a decrease of RNA and a stronger reactivity for acid phosphatase and beta-glucuronidase. The non-specific esterase showed a weaker reactivity in the cells with a larger amount of cholesterol and a stronger reaction in the cells with a smaller quantity of this substance. Several enzymes such as: diaphorases, those of the pentose shunt and respiratory cycle as well as those related to the metabolism of lipids, proteins and mucopolysaccharides showed a unconspicuous reactivity. The glycogen was found in a lesser amont in 6 out of 8 rabbits but with a higher concentration in 2 of them. The reactivity of UDPG-GT, active phosphorylase, F-1,6-PA, F-1,6-P Ald, LDH and ADH was stronger in the last 2 animals but weaker in the 6 others. In this 8 rabbit group the total phosphorylase and G-6-PA showed respectively always a stronger and a weaker reactivity than their controls. In the liver of 2 cholesterol-fed for 20 weeks rabbits it was observed a centrolobular fibrosis, a smaller amount of RNA and glycogen as well as a global decrease of the enzymatic reactivity.
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PMID:Histochemical reactions of liver cells in cholesterol-fed rabbits. 40 25

In isolated rat hepatocytes, cadmium (0-200 microM) decreased the overall glucuronidation of both isopropyl N-(3-chloro-4 hydroxyphenyl)carbamate (4-hydroxychlorpropham, 4-OHCIPC) and 4-nitrophenol in a concentration-dependent manner. In contrast, in native rat liver microsomes, glucuronidation of 4-OHCIPC was increased by cadmium through activation of microsomal 4-OHCIPC glucuronosyl transferase. In addition, in rat microsome incubations, the net amount of 4-OHCIPC glucuronide was also indirectly increased by cadmium through a reduction in the activity of beta-glucuronidase. As the effect of cadmium on the activity of 4-OHCIPC glucuronosyl transferase could not account for the decrease in glucuronide formation in intact hepatocytes, the influence of cadmium on the availability of UDP-glucuronic acid (UDPGA) was investigated further. In isolated rat hepatocytes, cadmium depleted the UDPGA content in a dose-dependent manner without a change in the UDP glucose (UDPG) content. Cadmium did not increase the breakdown of UDPGA by microsomal UDPGA pyrophosphatase but strongly decreased (30-66%) the synthesis of the cofactor in the cytosol by inhibiting UDP-glucose dehydrogenase (UDPGDH). Cadmium (10-50 microM) was found to inhibit the purified enzyme from bovine liver (EC 1.1.1.22) non-competitively. In vivo in the absence of a substrate undergoing glucuronidation, cadmium administration, 1.5 and 2.5 mg Cd/kg i.v., to normally fed rats resulted in a 15 and 30% decrease of hepatic UDPGA, respectively. However, in the liver, neither the NAD+/NADH ratio nor the UDPG content was significantly changed following cadmium treatment. Both in vitro and in vivo results support the conclusion that in intact cells the reduction in overall 4-OHCIPC glucuronidation caused by cadmium was due to a decrease in UDPGA availability which results from the inhibiting effect of cadmium on UDPGDH.
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PMID:Mechanism of cadmium-decreased glucuronidation in the rat. 147 79

Long-chain fatty acids inhibit glucuronidation of benzo(a)pyrene phenols in perfused liver; therefore, this study was designed to investigate interactions of fatty acids with beta-glucuronidase, glucuronosyl transferase, and energy supply. In beta-glucuronidase-deficient C3H/He mice, infusion of oleate (250 microM) increased the release of free benzo(a)pyrene phenols from 14 to 33 nmol/g/h and decreased release of glucuronides into the perfusate from 25 to 17 nmol/g/h. Rates of accumulation of glucuronides in the liver were also diminished from 11 to 4 nmol/g/h after infusion of oleate (250 microM). Fatty acids did not affect the release of benzo(a)pyrene metabolites into bile, and the ratio of free phenol to glucuronide production was increased from 0.57 to 1.30. A similar trend was observed in livers from DBA/2 mice that have beta-glucuronidase. Rates of hydrolysis of benzo(a)pyrene-O-glucuronide were not altered in isolated microsomes by addition of oleoyl coenzyme A (CoA) or octanoyl CoA (10- approximately 100 microM). Thus, we conclude that fatty acids do not alter glucuronidation by acting on beta-glucuronidase. The concentration of cofactors (UDP-glucuronic acid, UDP-glucose, and adenine nucleotides) involved in hepatic conjugation was not altered by infusion of concentrations of oleate (300 microM) that inhibited glucuronidation in perfused livers. When oleate concentrations were increased to 600 microM, UDP-glucuronic acid and UDP-glucose decreased 44 and 49%, respectively, and the ATP:ADP ratio declined concomitantly. Oleoyl CoA inhibited UDP-glucuronosyl transferase noncompetitively (half-maximal inhibition, 10 microM) in microsomes with 3-hydroxy-benzo(a)pyrene or p-nitrophenol as substrate. In contrast, octanoyl CoA was a very poor inhibitor of transferase activity. Inhibition of the transferase by oleoyl CoA was increased markedly by treatment with detergents (Triton X-100), i.e., half-inhibition of glucuronosyl transferase was obtained with about 2 microM oleoyl CoA. Inhibition of UDP-glucuronosyl transferase by oleoyl CoA was also increased in a dose-dependent manner by albumin, possibly due to increasing access of the CoA derivative to the enzyme. Collectively, these data indicate that fatty acids diminish glucuronidation via the formation of acyl CoA compounds that inhibit UDP-glucuronosyl transferase noncompetitively.
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PMID:Inhibition of glucuronidation of benzo(a)pyrene phenols by long-chain fatty acids. 190 48

Dibutyryl cyclic adenosine 3':5'-monophosphate (DBcAMP) has been shown to inhibit glucuronidation of p-nitrophenol in a concentration-dependent manner in isolated rat hepatocytes. Adenosine (ADO) also decreased glucuronidation in a similar fashion. The effects of adenosine were examined on the variables controlling glucuronidation in intact cells. The addition of adenosine was without effect on either glucuronyltransferase or beta-glucuronidase. Adenosine decreased uridine diphosphate glucuronic acid (UDPGA) levels by 62% and, subsequently, inhibited glucuronidation by 41% in isolated rat hepatocytes. Since the synthesis of UDPGA requires NAD+ for the dehydrogenation of UDP-glucose, alterations in the redox state could account for the decrease in intracellular UDPGA levels. The effects of ADO (500 microM) on lactate and pyruvate content and redox state were examined in rat hepatocytes. ADO caused a 2.1-fold increase in lactate levels and a 2.65-fold increase in the [lactate]/[pyruvate] ratio. The NAD+/NADP ratio, therefore, was decreased by 63% in the presence of ADO. Carbohydrate reserve also affects UDPGA levels; thus, graded concentrations of glucose (5.5, 25, and 50 mM) were added to cells incubated with ADO. At 5.5 mM glucose, ADO caused a 61% decrease in glucuronide formation, while at concentrations of 25 and 50 mM glucose, the inhibition was diminished by 53 and 47% respectively. ADO appears to have decreased the synthesis of UDPGA by decreasing the NAD+/NADH ratio, thus inhibiting UDP-glucose dehydrogenase. Carbohydrate reserve also appears to be involved in the inhibition of glucuronidation mediated by ADO.
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PMID:Effects of adenosine on glucuronidation and uridine diphosphate glucuronic acid (UDPGA) synthesis in isolated rat hepatocytes. 282 Apr 27

1. The thio-beta-d-glucosiduronic acids (thio-beta-glucuronides) of o-aminothiophenol, diethyldithiocarbamic acid, p-nitrothiophenol and thiophenol are formed biosynthetically in broken- and intact-cell preparations of mouse liver. 2. For this biosynthesis to occur in homogenates or microsomal fractions, UDP-glucuronic acid was required during incubation; glucose, glucuronic acid or UDP could not replace it. UDP was a product of the reaction. 3. The biosynthetic mechanism linking glucuronic acid to thiol and carbodithioic groups therefore requires UDP-glucuronyltransferase activity and resembles that forming the various types of O-glucuronides. 4. An analogous enzymic mechanism employing UDP-glucose synthesizes the thio-beta-d-glucosides of diethyldithiocarbamic acid and thiophenol in gut preparations of the mollusc Arion ater; this mechanism resembles that forming the O-glucosides. The thio-beta-d-glucosides are formed also in intact cells. 5. As expected from the distribution of O-glycosides, S-glucuronides of these aglycones were not detectable with the invertebrate, nor were the S-glucosides with the vertebrate. 6. Despite their similar biosyntheses, S- and O-beta-glycosides differ in susceptibility to hydrolysis by beta-glycosidases. Rat preputial-gland beta-glucuronidase hydrolysed thioglucuronides of o-aminothiophenol, diethyldithiocarbamic acid and p-nitrothiophenol, hydrolysis being inhibited by glucarolactone; the thioglucuronide of thiophenol was not hydrolysed by preputial-gland or liver beta-glucuronidase. The two S-glucosides resisted hydrolysis by beta-glucosidase from almond emulsin.
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PMID:Mechanism of biosynthesis of thio- -D-glucuronides and thio- -D-glucosides. 465 87

1. Rat liver microsomal preparation can effect the transglucosylation from UDP-glucose to bilirubin in the presence of Mg(2+). 2. Other nucleotides, namely CDP-glucose, ADP-glucose and GDP-glucose, were not active as glucosyl donors. 3. Only trace amounts of galactose, galacturonic acid and N-acetylglucosamine were conjugated to bilirubin when their respective UDP derivatives were used in the reaction mixture. 4. The azobilirubin glucosides produced by coupling with p-diazobenzenesulphonic acid and diazotized ethyl anthranilic acid were separable from the corresponding azobilirubin glucuronides by t.l.c. 5. The glucoside was, however, hydrolysed by both beta-glucosidase and various preparations of beta-glucuronidase; azobilirubin and glucose were liberated in the process. 6. Kinetic studies showed that the effects of pH and Mg(2+) on the two conjugating systems were similar. 7. The specific activities of hepatic bilirubin UDP-glucosyltransferase, expressed as mug of bilirubin ;equivalents' conjugated/h per mg of protein, are respectively 1.7 and 2.4 for male and female rats. 8. The K(m) values for bilirubin and UDP-glucose are 5.7x10(-5)m and 1.6x10(-3)m respectively. 9. The glucoside and glucuronide conjugations of bilirubin are discussed in relation to the availability of the conjugating agents and aglycone in the liver.
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PMID:Formation of bilirubin glucoside. 514 54

Sucrose synthase, an important enzyme in carbohydrate metabolism, catalyzes the reversible conversion of sucrose and UDP to UDP-glucose and fructose in vitro. To investigate the in vivo function of sucrose synthase, both the gene (Asus1) and a corresponding cDNA from roots of Arabidopsis were isolated. The Asus1 gene has homologies of 67-72% to sucrose synthase genes from other species. Histochemical GUS analysis of Arabidopsis and tobacco plants transformed with a 1.5 kb Asus1 promoter fragment transcriptionally fused to the beta-glucuronidase reporter gene showed that the Asus1 gene is expressed in the phloem of leaves, and in roots. Induction is found under conditions of limited ATP supply and increased demand for translocation of carbohydrates such as anaerobic or cold treatment. During anaerobiosis the increase in RNA level leads to increased sucrose synthase activity in roots. The expression pattern and regulation of the gene suggest that sucrose synthase is involved in the supply of energy for phloem loading in source tissues, and in metabolization of sucrose in sink tissues after unloading.
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PMID:Expression of an Arabidopsis sucrose synthase gene indicates a role in metabolization of sucrose both during phloem loading and in sink organs. 822 Apr 87


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