Mechanism of oxidation reactions catalyzed by cytochrome P450 enzymes

The cytochromes P450 constitute a large family of cysteinato-heme enzymes, are present in all forms of life, and play a key role in the oxidative transformation of endogeneous and exogenous molecules. Isolation and characterization of these enzymes first occurred some 45 years ago. Up to the present, the exact nature of the active species responsible for the oxygen insertion step is still a matter of intensive debates. This review discusses the different steps of the catalytic cycle of cytochrome P450 with particular attention to the iron oxygen-containing intermediates. It also covers mechanistic aspects of reactions catalyzed by cytochrome P450 enzymes.