Can function as a Delta(12)/Delta(15) bifunctional desaturase and behaves as a nu +3' desaturase. Introduces a double bond in the fatty acid chain three carbons away from an existing double bond to biosynthesize polyunsaturated fatty acids (PUFAs) endogenously (PUFAs are essential for membrane structure and many cellular and physiological processes). Acts on a number of substrates like oleoyl-CoA ((9Z)-octadecenoyl-CoA, 18:1n-9), palmitoleoyl-CoA ((9Z)-hexadecenoyl-CoA, 16:1n-7), and gamma-linolenoyl-CoA ((6Z,9Z,12Z)-octadecatrienoyl-CoA, 18:3n-6), to generate linoleoyl-CoA ((9Z,12Z)-octadecadienoyl-CoA, 18:2n-6), (9Z,12Z)-hexadecadienoyl-CoA (16:2n-4) and (6Z,9Z,12Z,15Z)-octadecatetraenoyl-CoA (18:4n-3) respectively. Unlike plants, Caenorhabditis elegans desaturases seem to use fatty acyl-CoAs as substrates (Probable).
