Stereochemistry of an alcohol oxidase from the defensive secretion of larvae of the leaf beetle Phaedon armoraciae (Coleoptera: Chrysomelidae).

Larvae of the leaf beetle Phaedon armoraciae produce the iridoids chrysomelidial 1 and plagiodial 3 from geraniol 6 by an oxidative sequence identical to that known in plants. Following omega-oxidation of geraniol the resulting 8-hydroxygeraniol 7 is ortidised via 8-oxogeraniol 14 and 8-hydroxygeranial 15 and to the dialdehyde 8. In plants this transformation is achieved by NADP(+) dependent oxidoreductases. However, in the defensive secretion of several leaf beetles an oxygen-dependent oxidase is present. The enzyme catalyses the removal of the C(1)- and C(8)-H-R hydrogen atoms (Re-specificity) from the diol 7 yielding 8-oxogeranial 8. Copyright (C) 1996 Elsevier Science Ltd