Activation of H2O2 by P450: evidence that the hydroxylating intermediate is iron(III)-coordinated H2O2 and not the ferryl FeO3+ complex

Abstract

Purified P4502B4 (LM2) catalyses the hydroxylation of lauric acid by H2O2 against a background of degradation of the porphyrin ring while iodosylbenzene, which rapidly forms the ferryl FeO3+ derivative, supports neither hydroxylation nor degradation and further inhibits degradation by added H2O2, indicating that the key intermediate in both hydroxylation and heme degradation is an FeIII peroxide complex.