Hydroperoxyflavin-mediated oxidations of organosulfur compounds. Model studies for the flavin monooxygenase.

Kinetic and product studies were carried out for the reaction of a synthetic hydroperoxyflavin with a series of organosulfur compounds as a model for the flavin-containing monooxygenase of mammalian liver (FMO). S-Oxidized products were identified, and the kinetics of the oxidation reactions were consistent with a mechanism involving attack of a sulfur nucleophile on the terminal oxygen atom of the hydroperoxyflavin. These results provide information about the substrate oxygenation step of FMO not available from steady-state enzyme kinetics.