Theoretical study on monooxygenation mechanism by cytochrome P450: an ultimate species in the substrate oxidation process

A reaction route for the monooxygenation in P450 by the proposed ultimate species [M. Hata, T. Hoshino, M. Tsuda, Chem. Commun. (2000) 2037] was investigated by using theoretical calculations. The ultimate species contains a spin singlet oxygen atom and leads to oxygen insertion into the C-H bond of the substrate. The activation energy of this insertion is only 4.2 kcal/mol, suggesting the possibility of a monooxygenation reaction induced by the ultimate species. The coexistence of two types of ultimate species, compound I and the proposed one, gives a good explanation for the observation of several kinds of final products in experiments on cytochrome P450.