Isolation and characterization of multiple forms of rat liver UDP-glucuronate glucuronosyltransferase.

摘要: UDP-glucuronosyltransferase (EC 2.4.1.17) activity was solubilized from male Wistar rat liver microsomal fraction in Emulgen 911, and six fractions with the transferase were separated by chromatofocusing on PBE 94 (pH 9.4 to 6.0). Fraction I further into Isoforms Ia, Ib Ic affinity chromatography UDP-hexanolamine-Sepharose 4B. III purified rechromatofocusing 8.7 7.5). UDP-glucuronosyltransferases Fractions IV V chromatography. The isoforms II, III, finally h.p.l.c. a TSK G 3000 SW column. Purified Ia (Mr 51,000), 52,000), 56,000), II 53,000) revealed single Coomassie Blue-stained bands sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Isoform enzyme showed two of Mr 52,000 53,000. Comparison amino acid compositions method Cornish-Bowden [(1980) Anal. Biochem. 105, 233-238] suggested that all are structurally related. Reverse-phase tryptic peptides individual distinct 'maps', indicating differences primary protein structure. electrophoretic peptide maps after limited enzymic proteolysis. After reconstitution phosphatidylcholine liposomes, exhibited but overlapping substrate specificities. specific for bilirubin glucuronidation, which not inhibited other aglycone substrates. Each isoform, except identified as glycoprotein periodic acid/Schiff staining.