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)

In studies with bromobenzene we found increases in the activities of hepatic lysosomal enzymes. The present study was undertaken to determine how these changes are related to the development of hepatic injury after bromobenzene administration. A single intraperitoneal injection of bromobenzene (5 mmoles/kg) caused significant increases in the total activity of lysosomal N-acetyl-beta-glucosaminidase and beta-glucuronidase in rat liver within 8-12 h, whereas it did not alter the free activity of these enzymes. Enhancement of bromobenzene hepatotoxicity by the pretreatment of rats with phenobarbital was not associated with further changes in hepatic N-acetyl-beta-glucosaminidase or beta-glucuronidase activities. Cycloheximide administered prior to bromobenzene inhibited significantly the effect of bromobenzene on the total N-acetyl-beta-glucosaminidase activity. The results suggest that lysosomal enzymes are not directly involved in hepatic damage caused by bromobenzene and that the inhibition of protein synthesis may reduce this response to hepatotoxin.
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PMID:Lysosomal enzymes in hepatic injury induced by bromobenzene. 27 13

A new method has been developed for measuring the total covalent binding of metabolically activated compounds to cellular macromolecules. This method employs equilibrium dialysis, in the presence of the detergent sodium dodecyl sulfate (SDS), to remove unbound radiolabeled compound and its metabolites from cellular macromolecules. [14C] Bromobenzene (80 microM), [14C]aflatoxin B1 (5 microM) or 3-[14C]methylcholanthrene (100 microM) was incubated (37 degrees C) with primary hepatocytes or liver microsomes isolated from Fischer-344 rats. The covalent binding of 14C-radiolabel to hepatic or microsomal macromolecules was measured by SDS-equilibrium dialysis and compared with that measured by exhaustive extraction. After 1 h of incubation with hepatocytes or microsomes, 2--7 times more covalent binding was detected by SDS-equilibrium dialysis, than by exhaustive extraction. The radioactivity associated with these hepatic or microsomal macromolecules migrated to discrete positions on SDS-polyacrylamide disc gels. The non-dialysable radioactivity from incubations with [14C] bromobenzene could not be extracted with diethyl ether even after treatment of the dialysin with beta-glucuronidase-sulfatase or dilute acid. This was taken to indicate that the radioactivity in the dialysin did not include free bromobenzene or its metabolites, a conclusion supported by thin-layer chromatography analysis of the dialysin. The lower amount of covalent binding detected by exhaustive extraction may be related to the inability of trichloroacetic acid to quantitatively precipitate small molecular weight macromolecules. SDS-equilibrium dialysis is an easy, rapid and non-destructive technique for measuring covalent binding. The macromolecular integrity of the sample is maintained and allows further studies concerning the specificity of the covalent interactions.
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PMID:A new method for measuring covalent binding of chemicals to cellular macromolecules. 742 16