Glucuronidation of retinoids by rat recombinant UDP: glucuronosyltransferase 1.1 (bilirubin UGT).
Rat liver recombinant BR1UGT1.1 was found to have significant activity toward retinoid substrates. UGT1.1 glucuronidation activity was 91 +/- 18 pmol/mg x min for atRA and 113 +/- 19 pmol/mg x 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 microM and 158 +/- 43 pmol/mg x 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 approximately 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 x min).
Radominska
A
A
Department of Medicine, University of Arkansas for Medical Sciences, Little Rock 72205, USA.
Little
J M
JM
Lehman
P A
PA
Samokyszyn
V
V
Rios
G R
GR
King
C D
CD
Green
M D
MD
Tephly
T R
TR
D000345:Affinity Labels; D000818:Animals; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D005965:Glucuronates / Q000378:metabolism; D014453:Glucuronosyltransferase / Q000378:metabolism*; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D007700:Kinetics; D008862:Microsomes, Liver / Q000201:enzymology; D011233:Precipitin Tests; D051381:Rats; D011911:Rats, Gunn; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000378:metabolism; D012176:Retinoids / Q000378:metabolism*; D013379:Substrate Specificity
D000345:Affinity Labels; D005965:Glucuronates; D007527:Isoenzymes; D011994:Recombinant Proteins; D012176:Retinoids; D014453:Glucuronosyltransferase