Omega- and (omega-1)-hydroxylation of lauric acid and arachidonic acid by rat renal cytochrome P-450.

We resolved four cytochrome P-450s, designated as P450 K-2, K-3, K-4, and K-5, from the renal microsomes of untreated male rats by high-performance liquid chromatography (HPLC) and investigated the lauric acid and arachidonic acid hydroxylation activities of these fractions. P450 K-4 and K-5 had high omega- and (omega-1)-hydroxylation activities toward lauric acid. The ratio of the omega-/(omega-1)-hydroxylation activity of P450 K-4 and K-5 was 3 and 6, respectively. Also, P450 K-4 and K-5 effectively catalyzed the omega- and (omega-1)-hydroxylation of arachidonic acid. P450 K-3 was not efficient in the hydroxylation of either lauric acid or arachidonic acid. P450 K-2 had low omega- and (omega-1)-hydroxylation activities toward arachidonic acid, and efficiently catalyzed the hydroxylation of lauric acid at the (omega-1)-position only, not at the omega-position.