Delta(12)-fatty acid desaturase producing in a heterologous system linoleic acid (18:2(9Z,12Z)) and to a lower extent hexadecadienoic acid (16:2(9Z,12Z)). Lipid metabolism; polyunsaturated fatty acid biosynthesis. The histidine box domains may contain the active site and/or be involved in metal ion binding. Belongs to the fatty acid desaturase type 1 family.