THE OXIDATION OF NAPHTHALENE AND PYRENE BY CYTOCHROME P450(CAM)

Mutants of the heme monooxygenase cytochrome P450(cam) in which Y96 ha d been replaced with hydrophobic residues, have been shown to oxidise naphthalene and pyrene with rates one to two orders of magnitude faste r than the wild-type. Naphthalene was oxidised to 1- and 2-naphthol, p robably via the 1,2-oxide intermediate, In the case of the Y96F mutant , naphthalene was oxidised at a rate comparable to camphor, Pyrene oxi dation gave 1,6- and 1,8-pyrenequinone with no evidence for attack at the K-region, in contrast to mammalian enzymes, The results show that the Y96 residue plays a key role in controlling the substrate range of P450(cam). (C) 1998 Federation of European Biochemical Societies.