Stearoyl-CoA 9-desaturase

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stearoyl-CoA 9-desaturase
EC no.
CAS no.9014-34-0
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO

In enzymology, a stearoyl-CoA 9-desaturase (EC 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[edit]


  • FULCO AJ, BLOCH K (1964). "Cofactor Requirements for the Formation of Delta-9-Unsaturated Fatty Acids in Mycobacterium Phlei". J. Biol. Chem. 239 (4): 993–7. doi:10.1016/S0021-9258(18)91378-5. 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 (January 1971). "A function of cytochrome b5 in fatty acid desaturation by rat liver microsomes". J. Biochem. Tokyo. 69 (1): 155–67. doi:10.1093/oxfordjournals.jbchem.a129444. 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.