The substrate preferences and "counting" mode of the cyanobacterial ω3 (Δ15) acyl-lipid desaturase.

Fatty acid desaturases (FADs) belong to of the oxygenase superfamily. They play important roles in metabolic pathways and adaption mechanisms in a wide range of organisms, including bacteria and humans. These enzymes dehydrogenate a single bond in the acyl chain of fatty acids (FAs), forming a double bond.