Isolation and characterization of a Delta 5-fatty acid desaturase from Caenorhabditis elegans.

Arachidonic acid and eicosapentaenoic acid are important precursors for the production of prostaglandins and other hormone-like eicosanoid molecules. These fatty acids are synthesized by animals by elongating and desaturating precursor fatty acids such as linoleic acid (18:2Delta9,12) and alpha-linolenic acid (18:3Delta9, 12,15). We have identified a Delta5 fatty acid desaturase gene (fat-4) from the nematode Caenorhabditis elegans. We have expressed this gene product in Saccharomyces cerevisiae and demonstrate that it readily converts di-homo-gamma-linolenic acid (20:3Delta8,11,14) to arachidonic acid (20:4Delta5,8,11,14). The FAT-4 Delta5-desaturase also acts on a number of other substrates, including fatty acids that do not contain a double bond at the Delta8 position.