Bisallylic Hydroxylation of Linoleic and Arachidonic Acids by Adult and Fetal Human Liver Microsomes and a Comparison with Human Recombinant Cytochromes P450

Cytochromes P450 (CYP) of liver microsomes can oxygenate polyunsaturated fatty acids1, 2. Hydroxylations of carbons at the ω end and epoxidations of the double bonds have attracted greatest attention. ω-Hydroxylation of polyunsaturated fatty acids is efficiently catalyzed by CYP4A, while other enzymes catalyze ω2 and ω3 hydroxylations of arachidonic acid (20: 4n-6). Enzymes of the CYP2B and CYP2C subfamily oxygenate 20: 4n-6 to epoxides1, 2, but all the constitutive epoxygenases may not have been identified.