Immunochemical analysis of cytochrome P450 monooxygenase diversity in the black swallowtail caterpillar, Papilio polyxenes

Antisera to nineteen cytochrome P450 monooxygenases were assayed for cross-reactivity with microsomal and mitochondrial proteins of the black swallowtail caterpillar, Papilio polyxenes (Lepidoptera:Papilionidae), on Western blots. Antisera to P450s from a bacterium, an insect and three mammals showed selective cross-reactivity with seven bands in the P450 molecular weight range of 45-60 kDa. Of the five putative P450s identified in midgut microsomes, only two were induced in larvae reared on a diet supplemented with high levels of xanthotoxin, a host plant constituent metabolized by P450 in the black swallowtail. The results confirm that insect P450s share conserved epitopes with P450s from other taxa and provide further evidence of the selective induction of P450 isozymes by xanthotoxin in black swallowtail larvae.