Abstract
Fatty acids are the major components of membrane molecules. The fact that unsaturated fattyacids play multiple important roles, physically and biologically, means that the ratio of unsaturatedto saturated fatty acids in the membrane needs to be strictly regulated to maintain cellular homeostasis.The most ubiquitous and widespread modification to fatty acids, which results in a greatdiversity of different structures, is the insertion of double bonds. Fatty acid desaturases directlyintroduce regioselective double bonds into fatty acids. A phylogenetic analysis of desaturases suggeststhat the sequences of these proteins include a highly conserved domain, which determines thedifferences in specificity and regioselectivity found in these enzymes. In this study, we performeda systematic analysis of fatty acid desaturases found in the genomic data of 397 organisms. Weobtained a set of desaturases clustered by regioselectivity using a hierarchal clustering analysis.