The P450morsystem fromMycobacteriumsp. strain HE5, supposed to cata-lyse the hydroxylation of different N-heterocycles, is composed of three components: ferredoxin reductase (FdRmor), Fe3S4 ferredoxin (Fd mor) and cytochrome P450 (P450mor). In this study, we purified Fdmorand P450mor as recombinant proteins as well as FdRmor, which has been isolated previ-ously. Kinetic investigations of the redox couple FdRmor⁄Fdmorrevealed a 30-fold preference for the NADH-dependent reduction of nitroblue tetrazo-lium (NBT) and an absolute requirement for Fd morin this reaction, com-pared with the NADH-dependent reduction of cytochromec. .
