Stearoyl-CoA 9-desaturase

In enzymology, a stearoyl-CoA 9-desaturase (EC 1.14.19.1) is an enzyme used to produce the monounsaturated fatty acid oleic acid from the saturated fatty acid stearic acid. It catalyzes the chemical reaction

stearoyl-CoA + 2 ferrocytochrome b₅ + O₂ + 2 H⁺ oleoyl-CoA + 2 ferricytochrome b₅ + 2 H₂O

The 4 substrates of this enzyme are stearoyl-CoA, ferrocytochrome b5, O₂, and H⁺, whereas its 3 products are oleoyl-CoA, ferricytochrome b5, and H₂O.

This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O₂ as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O₂ with oxidation of a pair of donors resulting in the reduction of O to two molecules of water. The systematic name of this enzyme class is stearoyl-CoA,ferrocytochrome-b5:oxygen oxidoreductase (9,10-dehydrogenating). Other names in common use include Delta9-desaturase, acyl-CoA desaturase, fatty acid desaturase, and stearoyl-CoA, hydrogen-donor:oxygen oxidoreductase. This enzyme participates in polyunsaturated fatty acid biosynthesis and ppar signaling pathway. It employs one cofactor, iron.

See also

• Fatty acid desaturase
• Fatty acid synthesis
• Cyclopropene acid

References

• FULCO AJ, BLOCH K (1964). "COFACTOR REQUIREMENTS FOR THE FORMATION OF DELTA-9-UNSATURATED FATTY ACIDS IN MYCOBACTERIUM PHLEI". J. Biol. Chem. 239: 993–7. PMID 14167617. 
• Oshino N, Imai Y, Sato R (1966). "Electron-transfer mechanism associated with fatty acid desaturation catalyzed by liver microsomes". Biochim. Biophys. Acta 128 (1): 13–27. doi:10.1016/0926-6593(66)90137-8. PMID 4382040. 
• Oshino N, Imai Y, Sato R. "A function of cytochrome b5 in fatty acid desaturation by rat liver microsomes". J. (Tokyo). Biochem. (1): 155–67. PMID 5543646. 
• Strittmatter P, Spatz L, Corcoran D, Rogers MJ, Setlow B, Redline R (1974). "Purification and properties of rat liver microsomal stearyl coenzyme A desaturase". Proc. Natl. Acad. Sci. U.S.A. 71 (11): 4565–9. doi:10.1073/pnas.71.11.4565. PMC 433928. PMID 4373719.