Nonenzymatic reduction of brucine N-oxide by the heme group of cytochrome P450.

Evidence showing that cytochrome P450-mediated reduction of brucine N-oxide to brucine by rat liver microsomes proceeds nonenzymatically in the presence of both a reduced pyridine nucleotide and FAD is presented. The microsomal N-oxide reduction appears to proceed in two steps: The first step is reduction of FAD by NADPH or NADH either enzymatically or nonenzymatically. The second step is nonenzymatic reduction of the tertiary amine N-oxide by the reduced flavin and is nonenzymatically catalyzed by the heme group of cytochrome P450.