[Interaction of 8-aza-16-oxasteroids with rat liver microsomal cytochrome P-450]

The interaction of the 8-aza-16-oxasteroid series (8-AS) with cytochrome P-450 from liver microsomes of intact and phenobarbital-induced rats has been studied. It has been shown that 8-AS are the substrates for the cytochrome P-450-dependent enzyme system, and that their affinity for cytochrome P-450 is determined by the structure of the compounds tested. Using inhibitory analysis, the site in the active center of hemoprotein responsible for 8-AS binding was examined. The possibility of direct participation of the 8-AS ketogroup in their binding with cytochrome P-450 is discussed.