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

Abstract

1. The role of vitamin K₁ in the hydroxylation of benzo(α)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 from 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.