BIOSYNTHESIS OF A DEFENSIVE INSECT ALKALOID - EPILACHNENE FROM OLEIC-ACID AND SERINE

The biosynthesis of the azamacrolide epilachnene by the coccinellid be etle Epilachna varivestis has been studied with H-2-labeled oleic acid , H-2-labeled L-serine, and C-13,N-15-labeled L-serine. The incorporat ion of these precursors into epilachnene defines the origin of the alk aloid's entire carbon/nitrogen skeleton. GC/MS and GC/IR studies of al kaloid produced by Epilachna fed with deuteriated oleic acid show that oleic acid loses four carbon atoms from its carboxyl end during the b iosynthesis. Other details, including the mechanism of carbon-nitrogen bond formation between the fatty acid and amino acid moieties, remain to be established.