The comparative study of peroxidase activities and substrate binding properties of cytochrome p450 2B4 in reconstituted vesicles prepared with the use of two different techniques, and microsomal cytochrome P450 was carried out. The data obtained show that the two types of cytochrome P450 2B4-containing proteoliposomes do not differ substantially from each other with respect to H2O2- or cumene hydroperoxide-dependent substrate hydroxylation activities as well as substrate binding properties of hemoprotein reconstituted. However, some parameters measured with proteoliposomal cytochrome P450 are markedly different from those measured with microsomal hemoprotein, suggesting the existence of conformational differences between the molecules of these two cytochromes or the differences in the depth of their immersion into lipid bilayer.