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

The cytochrome P-450-dependent monooxygenase in musk shrew (suncus; Suncus murinus) liver microsomes metabolized unsaturated fatty acids (oleic, linoleic, alpha-linolenic and arachidonic acids) to a variety of oxygenated products. alpha-Linolenic acid was the most active substrate. The oxygenation activity increased with an increase in the number of cis double-bonds in the C18 fatty acids. This suggests that the introduction of cis double-bonds in C18 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 omega- and (omega-1)-hydroxyarachidonic acids as major reaction products.