Enzymic hydroxylation of benzo(alpha)pyrene at the 6-position by vitamin K1-hydroperoxide and rat lung hydroperoxidase.

1. The role of vitamin K1 in the hydroxylation of benzo(alpha)pyrene (BP) at the 6-position is correlated with the oxidative formation of vitamin K1-hydroperoxide and its subsequent reaction with BP in the presence of soluble rat lung hydroperoxidase. 2. Vitamin K1-hydroperoxide was synthesized for vitamin K1 and its structure verified by mass spectral analysis and enzymic studies. 3. The major product (the 3,6-BP dione) that results from the non-enzymic oxidation of 6-hydroxy-BP was isolated from the enzymic reaction and characterized by spectroscopic studies. 4. Thiodione (the menadione-glutathione adduct) inhibits both aryl hydrocarbon hydroxylase activity and vitamin K1-hydroperoxide/hydroperoxidase activity.