Stereospecificity of the (Z)-9 desaturase that converts (E)-11-tetradecenoic acid into (Z,E)-9,11-tetradecadienoic acid in the biosynthesis of Spodoptera littoralis sex pheromone.

Moth pheromone glands contain desaturases that catalyze the formation of conjugated dienoic fatty acids. In this article we present the first stereochemical study on one of these enzymes, namely the Delta(9) desaturase of (E)-11-tetradecenoic acid, using the moth Spodoptera littoralis as a biological model and enantiopure deuterated probes derived from tridecanoic acid. Gas chromatography coupled to mass spectrometry analysis of methanolyzed lipidic extracts from glands incubated with each individual probe showed that in the transformation of (E)-11-tetradecenoic acid into (Z,E)-9,11-tetradecadienoic acid both pro-(R) hydrogen atoms at C9 and C10 are removed from the substrate.