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)

Dihydrodiol dehydrogenase (DD; EC 1.3.1.20) purified to homogeneity from rat liver cytosol will catalyze the NAD(P)(+)-dependent oxidation of (+/-)-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (B[a]P-diol) to yield benzo[a]pyrene-7,8-dione (BPQ). To verify that BPQ is a metabolite of B[a]P-diol in rat liver, an S100 fraction was supplemented with NAD+ and NADP+, and the formation of BPQ was followed by reverse-phase HPLC. The identity of BPQ was established by co-chromatography with an authentic standard (under different solvent conditions) and by RP-HPLC using a diode-array detector which established that the metabolite shared spectral identity with BPQ. The formation of BPQ in the S100 fraction was blocked by either a competitive inhibitor (indomethacin) or a suicide substrate [1-(4-nitrophenyl)-propen-1-ol] for DD, indicating that BPQ was being formed by this enzyme. To assess the contribution of DD to the metabolism of [3H]B[a]P-diol, subcellular fractions obtained from uninduced rat liver were fortified with co-factors to optimize the activity of enzymes that would compete for this proximate carcinogen. Under these conditions, S100 fractions fortified with NAD+ and NADP+ metabolized 25% of the B[a]P-diol, producing 731 +/- 154 pmol of BPQ. In contrast, rat liver microsomes fortified with an NADPH generating system metabolize 75% of the B[a]P-diol producing 2614 +/- 379 pmoles of benzo[a]pyrene-tetrahydrotetrols. Rat liver homogenates (S10) fortified with either uridine diphosphoglucuronic acid or phosphoadenosine phosphosulfate produced 180 +/- 56 and 95 +/- 31 pmoles of conjugates respectively, which were recovered as B[a]P-diol after treatment of the aqueous phase with either beta-glucuronidase or aryl sulfatase. Of the metabolites analyzed BPQ was formed in the second largest amount. These studies show that in uninduced rat liver DD may play a significant role in the metabolism of B[a]P-diol. The metabolic fate of BPQ remains to be determined.
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PMID:Contribution of dihydrodiol dehydrogenase to the metabolism of (+/-)-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene in fortified rat liver subcellular fractions. 139 42

Beta-glucuronidase activity in the bile may be of importance in the etiology of pigment gallstones. This enzyme is of hepatic or bacterial origin. We have described a method to measure the activity of bacterial beta-glucuronidase in human bile, using 4-nitrophenyl-beta-D-glucopyranosiduronic acid as substrate. The method was used to measure the beta-glucuronidase activity in the bile from 51 patients with gallstone disease. This activity was related to the presence of beta-glucuronidase-producing bacteria in the bile. Escherichia coli, Bacteroides species, and Clostridium perfringens were the only species found to produce beta-glucuronidase. Patients with beta-glucuronidase-producing bacteria had on an average significantly higher enzyme activity in the bile than patients without such bacteria (p less than 0.01). The limitations of using artificial substrates in this type of studies are discussed.
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PMID:Beta-glucuronidase activity related to bacterial growth in common bile duct bile in gallstone patients. 334 3

This paper reports the occurrence of beta-glucuronidase-producing bacteria in the bile in gallstone patients treated with endoscopic papillotomy (EPT). The study included 36 patients--18 women and 18 men, aged 43-87 years, with a median of 72.5 years. Bile sampling was done with an endoscopic technique. All bacterial strains were tested for beta-glucuronidase activity with a rapid chromogenic tablet test, using 4-nitrophenyl-beta-D-glucuronic acid as substrate. Bacterial growth was found in the bile in 35 patients. Of 103 strains isolated, 30 produced beta-glucuronidase. Twenty-five of the patients had at least one beta-glucuronidase-producing strain in the bile. All 26 strains of Escherichia coli were producing the enzyme. Both strains in the Bacteroides fragilis group and one out of two strains of Clostridium perfringens were producing beta-glucuronidase. The activity of the bacterial beta-glucuronidase was found within the pH range of the bile in these patients. A relationship between the presence of beta-glucuronidase-producing bacteria in the bile and pigment gallstone is suggested.
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PMID:Beta-glucuronidase-producing bacteria in bile from the common bile duct in patients treated with endoscopic papillotomy for gallstone disease. 371 93