Oxidation of pesticides by purified microsomal FAD-containing monooxygenase from mouse and pig liver

The ability of purified microsomal FAD-containing monooxygenase from mouse and pig liver to oxidize pesticides has been investigated. The kinetic constants, K_m and V_max, were determined for a number of pesticide substrates including thioether-containing organophosphorus compounds and carbamates as well as (di)alkyldithiocarbamates. In general, the mouse liver enzyme had K_m values higher than those of the pig liver enzyme. Values for V_max were similar regardless of substrate, although the V_max typical of the mouse liver enzyme was approximately twice that of the pig liver enzyme. The thioether-containing organophosphorus compounds were the best substrates for both enzymes followed by the thioether-containing carbamates. The (di)alkyldithiocarbamates were relatively poor substrates for both pig and mouse liver microsomal FAD-containing monooxygenases.