title: Protein-protein interactions between rat hepatic cytochromes P450 (P450s) and UDP-glucuronosyltransferases (UGTs): evidence for the functionally active UGT in P450-UGT complex.
abstract: The interaction between cytochrome P450s (CYP, P450) and UDP-glucuronosyltransferases (UGTs) was studied by co-immunoprecipitation. P450 isoform-selective antibody was used as a probe to co-precipitate UGTs with the P450s from solubilized rat liver microsomes. Antibodies toward CYP3A2, CYP2B2, CYP2C11/13 and CYP1A2 co-precipitated UGTs with corresponding P450s. However, calnexin, a type-I membrane protein, in the endoplasmic reticulum was not co-precipitated by anti-P450 antibodies. UGT activity toward 4-methylumbelliferone was detected in all co-precipitates, suggesting that UGT in the complex with P450s is functionally active. Repeated washing of co-immunoprecipitates revealed differences among P450 isoforms with regard to the affinity for UGT. Larger amounts of UGT1A1 and UGT1A6, compared with UGT2B1, were washed out from UGTs-CYP2C11/13 co-precipitates, whereas UGT-CYP3A2 and UGT-CYP2Bs complexes were resistant to thorough washing. Thus, CYP2C11/13 could associate with UGTs, but the affinity is assumed to be weaker than that of CYP2B/3As. These results suggest that there is isoform specificity in the interaction between P450s and UGTs.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ishii
authors.forename: Megumi
authors.initials: M
authors.lastname: Iwanaga
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Nishimura
authors.forename: Shuso
authors.initials: S
authors.lastname: Takeda
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Ikushiro
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Nagata
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Yamazoe
authors.forename: Peter I
authors.initials: PI
authors.lastname: Mackenzie
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Yamada
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism; D019388:Cytochrome P-450 CYP1A2 / Q000378:metabolism; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D000072467:Cytochrome P450 Family 2; D003580:Cytochromes; D014453:Glucuronosyltransferase / Q000378:metabolism*; D006923:Hymecromone / Q000031:analogs & derivatives / Q000378:metabolism; D047468:Immunoprecipitation; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D008862:Microsomes, Liver / Q000201:enzymology / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D017208:Rats, Wistar; D039181:Steroid 16-alpha-Hydroxylase / Q000378:metabolism; D013250:Steroid Hydroxylases / Q000378:metabolism; D013379:Substrate Specificity; D000099148:UGT1A1 Enzyme
chemical_list: D001189:Aryl Hydrocarbon Hydroxylases; D019388:Cytochrome P-450 CYP1A2; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System; D000072467:Cytochrome P450 Family 2; D003580:Cytochromes; D014453:Glucuronosyltransferase; D006923:Hymecromone; D008565:Membrane Proteins; D009097:Multienzyme Complexes; D039181:Steroid 16-alpha-Hydroxylase; D013250:Steroid Hydroxylases; C499946:Ugt1a1 protein, rat; D000099148:UGT1A1 Enzyme; C450279:CYP2C11 protein, rat; C017170:Cyp1a2 protein, rat; C113764:Cyp2c13 protein, rat; C465260:Cyp3a2 protein, rat; C025619:steroid 16-beta-hydroxylase; C107611:UDP-glucuronosyltransferase, UGT1A7