Oxygenation of unsaturated fatty acids by hepatic microsomes of musk shrew ( Suncus murinus)

Abstract

The cytochrome P-450-dependent monooxygenase in musk shrew (suncus; Suncus murinus) liver microsomes metabolized unsaturated fatty acids (oleic, linoleic, α-linolenic and arachidonic acids) to a variety of oxygenated products. α-Linolenic acid was the most active substrate. The oxygenation activity increased with an increase in the number of cis double-bonds in the C 18 fatty acids. This suggests that the introduction of cis double-bonds in C 18 fatty acids is important for the binding of cytochrome P-450 in suncus liver microsomes. Regioselectivity of arachidonic acid oxygenation was observed in suncus liver microsomes; rat liver microsomal cytochrome P-450 generated epoxyeicosatrienoic acids and dihydroxyeicosatrienoic acid as major products while the cytochrome P-450-dependent monooxygenase in suncus liver microsomes yielded ω- and (ω-1)-hydroxyarachidonic acids as major reaction products.