Evidence of binary complex formations between cytochrome P-450, cytochrome b5, and NADPH-cytochrome P-450 reductase of hepatic microsomes.
Water-soluble carbodiimide-catalyzed cross-linking of purified cytochrome P-450 LM2, cytochrome b5, and NADPH-cytochrome P-450 reductase was used to identify stable complexes formed between these proteins. High yields of P-450-b5 and P-450 reductase-b5 dimers, and lower yields of P-450 reductase-LM2 dimers were obtained. Substitution of native b5 and P-450 reductase with fully amidinated derivatives showed that LM2 and b5 were cross-linked exclusively through their respective amino and carboxyl groups. However, there appeared to be two complexation sites on the reductase which cross-link to b5 through amino groups and to LM2 through carboxyl groups respectively. A heterotrimer could not be identified following incubation of all three proteins together with EDC.
Tamburini
P P
PP
MacFarquhar
S
S
Schenkman
J B
JB
D000818:Animals; D003432:Cross-Linking Reagents; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D003573:Cytochrome b Group / Q000378:metabolism*; D015786:Cytochromes b5; D046911:Macromolecular Substances; D008862:Microsomes, Liver / Q000201:enzymology* / Q000648:ultrastructure; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism*; D010634:Phenobarbital / Q000494:pharmacology; D011817:Rabbits
D003432:Cross-Linking Reagents; D003573:Cytochrome b Group; D046911:Macromolecular Substances; D015786:Cytochromes b5; D003577:Cytochrome P-450 Enzyme System; D009251:NADPH-Ferrihemoprotein Reductase; D010634:Phenobarbital