Stimulation of microsomal N-demethylation by solubilized NADPH-cytochrome c reductase

The addition of solubilized NADPH-cytochrome c reductase to phenobarbital pretreated microsomes increases both the Vm value for the N-demethylation of S(+)-N, N-dimethylamphetamine and the total level of reductase activity sedimenting with microsomes. Preliminary data indicate that the increase in Vm is a nonlinear function of added reductase and demonstrates saturation at a N-demethylase level approximately five times greater than the endogenous activity. These results indicate that the added reductase is bound to microsomes and is capable of functionally coupling with the cytochrome P₄₅₀ monooxygenase system.