Parathion, malathion and their oxygenated analogs bind to the reduced form of cytochrome P-450 from rats and mice producing spectra with a maximum at 421 nm and a minimum at 450 nm. Determinations of microsomal heme suggest that the Soret at 421 nm is not associated with conversion of cytochrome P-450 to cytochrome P-420. In vivo pretreatment with C14-parathion indicates that this insecticide covalently binds to mouse hepatic microsomal protein. These findings suggest that the mechanism by which these insecticides and their analogs inhibit hepatic microsomal metabolism is identical to their mode of inhibiting esterases, that is, covalent binding to catalytic site. © 1974.
Stevens, J. T. (1974). The role of binding in inhibation of hepatic microsomal metabolism by parathion and malathion. Life Sciences, 14(11), 2215–2229. https://doi.org/10.1016/0024-3205(74)90104-0