Glucuronidation of retinoids by rat recombinant UDP: glucuronosyltransferase 1.1 (bilirubin UGT)
Radominska, A.; Little, J.M.; Lehman, P.A.; Samokyszyn, V.; Rios, G.R.; King, C.D.; Green, M.D.; Tephly, T.R.
Drug Metabolism and Disposition the Biological Fate of Chemicals 25(7): 889-892
1997
ISSN/ISBN: 0090-9556 PMID: 9224784 Document Number: 473608
Rat liver recombinant BR-1UGT1.1 was found to have significant activity toward retinoid substrates. UGT1.1 glucuronidation activity was 91 +- 18 pmol/mg times min for atRA and 113 +- 19 pmol/mg times min for 5,6-epoxy-atRA. The apparent K-m and V-max of atRA acid glucuronidation by UGT1.1 were 59.1 +- 5.4 mu-M and 158 +- 43 pmol/mg times min, respectively. SDS-PAGE and Western blot analysis of UGT1.1-transfected HK293 membrane proteins photolabeled with (11,12-3H)atRA revealed a protein of apprx 56 kDa that was labeled by (3H)atRA, detected by anti-pNP UGT antibody and not present in membranes from nontransfected HK293 cells. Liver microsomes from Gunn rats, which lack UGT1.1, had significant activity toward atRA (111 +- 28 pmol/mg times min).