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 (18:2 Delta(9,12)) and alpha-l inolenic acid (18:3 Delta(9,12,15)). We have identified a Delta(5) fatty ac id desaturase gene (fat-4) from the nematode Caenorhabditis elegans. We hav e expressed this gene product in Saccharomyces cerevisiae and demonstrate t hat it readily converts di-homo-gamma-linolenic acid (20:3 Delta(8,11,14)) to arachidonic acid (20:4 Delta(5,8,11,14)). The FAT-4 Delta(5)-desaturase also acts on a number of other substrates, including fatty acids that do no t contain a double bond at the Delta(8) position. (C) 1999 Academic Press.