Isolation of a new form of cytochrome P-450 with prostaglandin A and fatty acid omega-hydroxylase activities from rabbit kidney cortex microsomes.

Two different forms of cytochrome P-450, highly active in the omega-hydroxylation of prostaglandin A, and the omega- and (omega-1)-hydroxylation of fatty acids (P-450ka-1 and P-450ka-2), have been purified from kidney cortex microsomes of rabbits treated with di(2-ethylhexyl)-phthalate. On the basis of the peptide map patterns and NH2-terminal amino acid sequence, P-450ka-1 was determined to be a new form of omega-hydroxylase cytochrome P-450, whereas P-450ka-2 is identical to P-450ka reported earlier. The first 20 NH2-terminal amino acid sequence (ALNPTRLPGSLSGLLQVAGL) and (ALSPTRLPGSFSGFLQAAGL) of P-450ka-1 and P-450ka-2 showed 90 and 80% homology with that of the lung prostaglandin omega-hydroxylase, respectively, suggesting that these three cytochromes P-450 are members of the same omega-hydroxylase cytochrome P-450 gene family.