Linoleoyl-CoA desaturase
| linoleoyl-CoA desaturase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC no. | 1.14.19.3 | ||||||||
| CAS no. | 9014-34-0 | ||||||||
| Alt. names | D6D, FADS2, acyl-CoA 6-desaturase, delta-6-desaturase | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
| |||||||||
Linoleoyl-CoA desaturase (also Delta 6 desaturase, EC 1.14.19.3) is an enzyme that converts between types of fatty acids, which are essential nutrients in the human body. The enzyme mainly catalyzes the chemical reaction
- linoleoyl-CoA + AH2 + O2 gamma-linolenoyl-CoA + A + 2 H2O
The three substrates of this enzyme are linoleoyl-CoA, an electron acceptor AH2, and O2, whereas its three products are gamma-linolenoyl-CoA, the reduction product A, 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 linoleoyl-CoA,hydrogen-donor:oxygen oxidoreductase. Other names in common use include acyl-CoA 6-desaturase, Delta6-desaturase (D6D or Δ-6-desaturase), Delta6-fatty acyl-CoA desaturase, Delta6-acyl CoA desaturase, fatty acid Delta6-desaturase, fatty acid 6-desaturase, linoleate desaturase, linoleic desaturase, linoleic acid desaturase, linoleoyl CoA desaturase, linoleoyl-coenzyme A desaturase, and long-chain fatty acid Delta6-desaturase. This enzyme participates in linoleic acid metabolism. It employs one cofactor, iron.
The enzyme is molecularly identical across all living things. It is present in animals, plants, fungi, and cyanobacteria.[1][2]
D6D is one of the three fatty acid desaturases present in humans along with Δ-5 and Δ-9, named so because it was thought to desaturate bond between carbons 6 and 7, counting from carboxyl group (with the carboxyl group carbon numbered one). The number 6 in the name of the enzyme has nothing to do with omega-6 fatty acids. In humans, D6D is encoded by the FADS2 gene.
Function
D6D is a desaturase enzyme, i.e. it introduces a double bond in a specific position of long-chain fatty acids. D6D is necessary to synthesize longer chain omega-3 and omega-6 fatty acids.[3] In humans, it is used principally for the conversions of cis-linoleic acid to gamma-linolenic acid (GLA), and palmitic acid to sapienic acid. It also converts alpha-linolenic acid (ALA) to stearidonic acid and tetracosatetraenoic acid to tetracosapentaenoic acid, intermediate steps in the synthesis of ALA to EPA and of EPA to DHA, respectively.
Toxoplasma gondii
Felines lack D6D activity in their guts and accumulate systemic linoleic acid.[4] This increase in linoleic acid in cats has an influence in causing the sexual cycle of Toxoplasma gondii to be restricted to felines, with linoleic acid stimulating T. gondii sexual reproduction.[5]
References
- ^ Lee JM, Lee H, Kang S, Park WJ (January 2016). "Fatty Acid Desaturases, Polyunsaturated Fatty Acid Regulation, and Biotechnological Advances". Nutrients. 8 (1): 23. doi:10.3390/nu8010023. PMC 4728637. PMID 26742061.
- ^ Nakamura MT, Nara TY (2004). "Structure, function, and dietary regulation of Δ6, Δ5, and Δ9 desaturases". Annual Review of Nutrition. 24: 345–376. doi:10.1146/annurev.nutr.24.121803.063211. PMID 15189125.
- ^ Meena DK. "HUFA and PUFA: Structures, Occurrence, Biochemistry And Their Health Benefits". Aquafind Aquatic Fish Database.
- ^ Sinclair, A. J.; McLean, J. G.; Monger, E. A. (1979). "Metabolism of linoleic acid in the cat". Lipids. 14 (11): 932–936. doi:10.1007/BF02533508. ISSN 1558-9307. PMID 513981. S2CID 4023638.
- ^ Martorelli Di Genova B, Wilson SK, Dubey JP, Knoll LJ (August 2019). "Intestinal delta-6-desaturase activity determines host range for Toxoplasma sexual reproduction". PLOS Biology. 17 (8) e3000364. doi:10.1371/journal.pbio.3000364. PMC 6701743. PMID 31430281.
- Okayasu T, Nagao M, Ishibashi T, Imai Y (1981). "Purification and partial characterization of linoleoyl-CoA desaturase from rat liver microsomes". Arch. Biochem. Biophys. 206 (1): 21–28. doi:10.1016/0003-9861(81)90061-8. PMID 7212717.