ABSTRACT: Caenorhabditis elegans FAT-2 has been characterized as fatty acid Δ12-desaturase able to desaturate C16 and C18 fatty acids. However, in this report we show that when expressed in yeast cells this enzyme can also catalyze Δ15 desaturation. This results in the production of both linoleic acid (ω6 C18:2Δ9,12) and linolenic acid (ω3 C18:3Δ9,12,15) from oleic acid (C18:1Δ9) substrate, and hexadecadienoic acid (ω4 C16:2Δ9,12) and hexadecatrienoic acid (ω1 C16:3Δ9,12,15) from palmitoleic acid (C16:1Δ9) substrate. In addition, this enzyme can also produce C14:2Δ9,12, C15:2Δ9,12, C17:2Δ9,12, and C18:4Δ6,9,12,15 when C14:1Δ9, C15:1Δ9, C17:1Δ9, and C18:3Δ6,9,12 substrates are available in yeast cells. Mass spectrometry analysis of 2,4-dimethyloxazoline modification of fatty acid methyl esters confir
