Pheromone biosynthesis chain-shortening enzymes

The above examples illustrate the use of deuterium labeling to help determine the most likely pathway for biosynthesis of pheromone components. The key components of these pathways are fatty acid biosynthesis, desaturation, chain shortening and specific enzymes to produce a functional group. 

Changes in reductase activity could result in altered pheromone amounts. The lightbrown apple moth, Epiphyas postvittana, exhibits a decline in pheromone titers with age that is not due to reduced PBAN levels (Foster and Roelofs, 1994). To determine what is responsible for the decline in titers, different deuterium-labeled precursors were applied to the glands of different aged females. Biosynthesis of the major pheromone component, Ell-14 OAc, occurs by chain shortening 16 acid to 14 acid followed by Ell desaturation, reduction, and acetylation (Foster and Roelofs, 1990). Application of deuterium-labeled intermediates indicated that the senescent decline in pheromone titers was due to the reduction in fatty acid reductase activity (Foster and Greenwood, 1997). It is unknown if a decline in reductase enzyme activity is also responsible for observed senescent decline in pheromone titers of other female moths (Foster and Greenwood, 1997). 

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