title: Substrate specificity and properties of uridine diphosphate glucuronyltransferase purified to apparent homogeneity from phenobarbital-treated rat liver.
abstract: 1. The purification to homogeneity of stable highly active preparations of UDP-glucuronyltransferase from liver of phenobarbital-treated rats is briefly described. 2. A single polypeptide was visible after sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, of mol.wt.57000. 3. Antiserum raised against the pure enzyme produces a single sharp precipitin line after Ouchterlony double-diffusion analysis. 4. The pure UDP-glucuronyltransferase isolated from livers of untreated and phenobarbital-pretreated rats appears to be the same enzyme. 5. The Km (UDP-glucuronic acid) of the pure enzyme is 5.4 mM. 6. The activity of the pure enzyme towards 2-aminophenol can still be activated 2-3-fold by diethylnitrosamine. 7. UDP-glucose and UDP-galacturonic acid are not substrates for the purified enzyme. 8. The final preparation catalysed the glucuronidation of 4-nitrophenol, 1-naphthol, 2-aminophenol, morphine and 2-aminobenzoate. 9. Activities towards 4-nitrophenol, 1-naphthol and 2-aminophenol were all copurified. The proposed heterogeneity of UDP-glucuronyltransferase is discussed.
mesh_terms: D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D014453:Glucuronosyltransferase / Q000302:isolation & purification / Q000378:metabolism; D005779:Immunodiffusion; D066298:In Vitro Techniques; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats; D013379:Substrate Specificity; D014539:Uridine Diphosphate Sugars / Q000378:metabolism
chemical_list: D014539:Uridine Diphosphate Sugars; D014453:Glucuronosyltransferase; D010634:Phenobarbital