Properties of the Δ11‐desaturase enzyme used in cabbage looper moth sex pheromone biosynthesis

The biosynthesis of a large number of sex pheromone components of various moth species can be explained by invoking a Δ 11‐desaturation of common fatty acids. A Δ11‐desaturase system from Trichoplusia ni, the cabbage looper moth, is identified and partially purified. Some of its properties are defined and compared with those of the ubiquitous Δ‐9 desaturase enzyme. Similarities between the two systems include subcellular location (microsomal), substrate specificity (16‐ and 18‐carbon acids), and lack of sensitivity to carbon monoxide, while differences include cofactor preference (NADH rather than NADPH), sensitivity to cyanide ion, pH optimum (7.4‐7.8 vs 6.8‐7.2), and location in the organism (in the pheromone gland compared to generally distributed). The effects of insect age were also investigated.