InterPro domain: IPR005067

Fatty acid desaturases are enzymes that catalyze the insertion of a double bond at the delta position of fatty acids.

There seem to be two distinct families of fatty acid desaturases which do not seem to be evolutionary related.

Family 1 is composed of:

• Stearoyl-CoA desaturase (SCD) ( 1.14.19.1 ) [ 1 ].

Family 2 is composed of:

• Bacterial fatty acid desaturases.
• Plant stearoyl-acyl-carrier-protein desaturase ( 1.14.19.1 ) [ 2 ], 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 [ 3 ], 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.

This entry contains fatty acid desaturases belonging to Family 2, also known as Acyl-ACP (Acyl Carrier Protein) desaturases.

1. Differentiation-induced gene expression in 3T3-L1 preadipocytes. A second differentially expressed gene encoding stearoyl-CoA desaturase. J. Biol. Chem. 264, 14755-61
2. Stearoyl-acyl-carrier-protein desaturase from higher plants is structurally unrelated to the animal and fungal homologs. Proc. Natl. Acad. Sci. U.S.A. 88, 2510-4
3. Enhancement of chilling tolerance of a cyanobacterium by genetic manipulation of fatty acid desaturation. Nature 347, 200-3