Comparison of vitamin D hydroxylation activities of rat CYP2J3 and human CYP2J2

Recombinant rat CYP2J3 and human CYP2J2 were successfully expressed in the E. coli expression system by co-expression of chaperone proteins. Purified proteins were applied to analysis of catalytic activities toward vitamin D compounds using a reconstituting system containing NADPH-P450 reductase. The CYP2J2 showed significant but about 10 times lower 25-hydroxylation activities than CYP2J3 toward vitamin D-3 and 1 alpha-OH-D-3. Interestingly, CYP2J2 prefers vitamin D-2 to vitamin D-3 as a substrate, whereas CYP2J3 did vitamin D-3 to vitamin D-2, The results suggest involvement of CYP2J subfamily proteins in vitamin D activation through 25-hydroxylation reaction, although they showed distinct preferences and activities toward vitamin D compounds.