| Abstract: | Oxidation of 1-piperidinoantraquinone (1-PA) in microsomal fractions of rat liver was studied. The only product of complete oxidation of 1-PA--(N-antraquinone-1)-delta-aminovaleric acid-was identified using paper and thin-layer chromatography. The participation of cytochrome P-450 in oxidation of 1-PA was demonstrated by sharp inhibition, involving blowing of the microsomes with CO and treatment with sodium deoxycholate. Studies of differential spectra of cytochrome P-450 in the presence of 1-PA are indicative of the first type of binding between 1-PA and cytochrome P-450. The binding constants (Ks) and the kinetic parameters (Km and V) for the above substrate in control microsomes and in those induced by phenobarbital and 3-methyl cholanthrene were determined. The results obtained suggest that cytochrome P-450 is involved in oxidation of a number of heterocyclic compounds resulting in the opening of the ring. |
