Fatty Acid Desaturase - Classification

Classification

Δ-desaturases are represented by two distinct families which do not seem to be evolutionary related.

Family 1 includes Stearoyl-CoA desaturase-1 (SCD) (EC 1.14.19.1).

Family 2 is composed of:

• - Bacterial fatty acid desaturases.
• - Plant stearoyl-acyl-carrier-protein desaturase (EC 1.14.19.1), this enzyme catalyzes the introduction of a double bond at the delta(9) position of steraoyl-ACP to produce oleoyl-ACP. This enzyme is responsible for the conversion of saturated fatty acids to unsaturated fatty acids in the synthesis of vegetable oils.
• - Cyanobacterial DesA, an enzyme that can introduce a second cis double bond at the delta(12) position of fatty acid bound to membranes glycerolipids. DesA is involved in chilling tolerance; the phase transition temperature of lipids of cellular membranes being dependent on the degree of unsaturation of fatty acids of the membrane lipids.