Interaction between cytochrome P-448 and NADP-cytochrome P-450 reductase in reconstituted microsomal membranes
Grishanova, A.Iu.; Mishin, V.M.; Liakhovich, V.V.
Biokhimiia 50(3): 369-374
1985
ISSN/ISBN: 0320-9725 PMID: 3995100 Document Number: 264522
The regularities of changes in the functional activity of the microsomal monooxygenase system reconstituted by self-assembly from intact rat liver microsomes solubilized with 4% sodium cholate were studied at variable levels of NADPH-cytochrome P-450 reductase and the 3-methylcholantrene-induced form of cytochrome P-450. Using antibodies against cytochrome P-448, the role of cytochrome P-448 in the overall reaction of benzpyrene hydroxylation induced in the microsomal membrane by a set of molecular forms of cytochrome P-450 was investigated. The effect of NADPH-cytochrome P-450 reductase and cytochrome P-448 incorporation into reconstituted microsomal membranes on benzpyrene metabolism suggests that in intact microsomal membranes benzpyrene metabolism induced by different forms of cytochrome P-450, with the exception of P-448, is limited by reductase. For cytochrome P-448 involved in the benzpyrene hydroxylation reaction, reductase is not the limiting component; however, cytochrome P-448 reveals its maximum activity at the cytochrome to reductase optimal molar ratio of 5:1; above this level, the catalytic activity of cytochrome P-448 is lowered.