PURIFICATION AND CHARACTERIZATION OF RABBIT SMALL-INTESTINAL CYTOCHROMES P450 BELONGING TO CYP2J AND CYP4A SUBFAMILIES

A new form of P450 designated P450ib2 was purified from rabbit small i ntestine microsomes. This P450 had properties very similar to P450ib ( CYP2J1), and showed 88% identity with CYP2J1 in its first 20 NH2-termi nal amino acid sequence, excluding 3 undetermined residues, Both P450i b and P450ib2 were immunohistochmically detected in the mucosal epithe rial cells of the duodenum, jejunum, and ileum in the small intestine, whereas no immunoreactivity was observed in other tissues including l iver, kidney, lung, colon, and stomach. The results support that the t wo closely related P450s are specifically localized in the rabbit smal l intestine. Another small intestinal P450, P450ia, was found to hydro xylate a wide variety of fatty acids including straight-chain, branche d-chain, unsaturated, or hydroxy fatty acids, and prostaglandin A at t he omega and (omega-1) positions. P450ia was identical with a rabbit k idney fatty acid omega-hydroxylase, CYP4A7, in its 25 NH2-terminal ami no acid sequence, excluding 2 undetermined residues. The results ident ify P450ia as CYP4A7. (C) 1997 Academic Press.