Pathway Tools
Intro Tutorial
discounted registration ends Sept 5, 2015
Pathway Tools
Intro Tutorial
discounted registration ends Sept 5, 2015
Pathway Tools
Intro Tutorial
discounted registration ends Sept 5, 2015
Pathway Tools
Intro Tutorial
discounted registration ends Sept 5, 2015
Pathway Tools
Intro Tutorial
discounted registration ends Sept 5, 2015
twitter

Homo sapiens Enzyme: acyl-CoA 6-desaturase

Gene: FADS2 Accession Number: HS05918 (HumanCyc)

Synonyms: SLL0262, LLCDL2, FADSD6, TU13, DES6, D6D, Δ6 fatty acid desaturase, linoleoyl-CoA desaturase, fatty acid desaturase 2

Component of: Δ6 linoleoyl-CoA desaturase complex

Summary:
The human Δ6 desaturase is encoded by the FADS2 gene, a member of the FADS family. The gene is clustered with two more desaturase genes within 92 kb of genomic DNA on chromosome 11 [Marquardt00]. The enzyme forms a microsomal membrane-bound three-component enzyme complex that also includes cytochrome b5 and NADH-cytochrome b5 reductase 3 [Tocher].

FADS family members are considered fusion products composed of an N-terminal cytochrome b5-like domain and a C-terminal multiple membrane-spanning desaturase portion, both of which are characterized by conserved histidine motifs [Marquardt00].

The human gene has been cloned, characterized, and expressed in rat hepatocytes and Chinese hamster ovary cells, where it conferred on the cells the ability to convert 18:2(n-6) and 18:3(n-3) fatty acids to their respective products [Cho99].

The enzyme is expressed in a wide array of tissues, highest expression is found in liver followed by brain, lung, heart, and retina [Marquardt00, Lane03].

In both fungi and animals, fatty acid desaturation generally utilize CoA-linked substrates, unlike plant enzymes, which usually desaturate the fatty acids while esterified into lipids (see γ-linolenate biosynthesis I (plants)). The enzyme catalyzes the desaturation of α-linolenoyl-CoA to stearidonoyl-CoA, linoleoyl-CoA to γ-linolenoyl-CoA [Cho99], and also the desaturation of palmitate to the mono-unsaturated fatty acid sapienate, the most abundant fatty acid in sebum [Ge03].

Citations: [Nara02, Stohr98]

Locations: plasma membrane, endoplasmic reticulum membrane

Map Position: [63,159,476 -> 63,210,514] (46.26 centisomes) on Chromosome 11
Length: 51039 bp

Unification Links: ArrayExpress:O95864 , Ensembl:ENSG00000134824 , Entrez-gene:9415 , Entrez-Nucleotide:AF084559 , Entrez-Nucleotide:AF108658 , Entrez-Nucleotide:AF126799 , Entrez-Nucleotide:AK074925 , Entrez-Nucleotide:AK074939 , Entrez-Nucleotide:AK074991 , Entrez-Nucleotide:AL050118 , Entrez-Nucleotide:BC009011 , GeneCards:FADS2 , Mint:MINT-2866355 , OMIM:606149 , PhosphoSite:O95864 , PhylomeDB:O95864 , Pride:O95864 , Protein Model Portal:O95864 , RefSeq:NM_004265 , RefSeq:NP_004256 , SMR:O95864 , String:9606.ENSP00000278840 , UCSC Human Genome:NM_004265 , UniGene:184641 , UniProt:O95864

Relationship Links: InterPro:IN-FAMILY:IPR001199 , InterPro:IN-FAMILY:IPR005804 , InterPro:IN-FAMILY:IPR012171 , Pfam:IN-FAMILY:PF00173 , Pfam:IN-FAMILY:PF00487 , Prosite:IN-FAMILY:PS50255

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

GO Terms:

Biological Process: GO:0006636 - unsaturated fatty acid biosynthetic process
GO:0022900 - electron transport chain
Molecular Function: GO:0016491 - oxidoreductase activity
Cellular Component: GO:0005789 - endoplasmic reticulum membrane
GO:0005887 - integral component of plasma membrane

Credits:
Created 06-Aug-2008 by Caspi R , SRI International


Enzymatic reaction of: tetracosapentaenoyl-CoA 6-desaturase (acyl-CoA 6-desaturase)

EC Number: 1.14.19.3

(9Z,12Z,15Z,18Z,21Z)-tetracosapentaenoyl-CoA + 2 a ferrocytochrome b5 + oxygen + 2 H+ <=> (6Z,9Z,12Z,15Z,18Z,21Z)-tetracosahexaenoyl-CoA + 2 a ferricytochrome b5 + 2 H2O

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

In Pathways: docosahexaenoate biosynthesis III (mammals)

Credits:
Imported from MetaCyc 17-Apr-2015 by Caspi R , SRI International


Enzymatic reaction of: linoleoyl-CoA 6-desaturase (acyl-CoA 6-desaturase)

Synonyms: Δ6 linoleoyl-CoA desaturase

EC Number: 1.14.19.3

linoleoyl-CoA + an unknown reduced electron acceptor + oxygen <=> γ-linolenoyl-CoA + an unknown oxidized electron acceptor + 2 H2O

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

In Pathways: γ-linolenate biosynthesis


Enzymatic reaction of: α-linolenoyl-CoA 6-desaturase (acyl-CoA 6-desaturase)

Synonyms: α-linolenate Δ6-desaturase

EC Number: 1.14.19.3

α-linolenoyl-CoA + 2 a ferrocytochrome b5 + oxygen + 2 H+ <=> stearidonoyl-CoA + 2 a ferricytochrome b5 + 2 H2O

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

In Pathways: icosapentaenoate biosynthesis II (metazoa)

Credits:
Imported from MetaCyc 17-May-2012 by Caspi R , SRI International


Subunit of: Δ6 linoleoyl-CoA desaturase complex

Subunit composition of Δ6 linoleoyl-CoA desaturase complex = [FADS2][CYB5A][CYB5R3]
         acyl-CoA 6-desaturase = FADS2 (extended summary available)
         cytochrome b5 = CYB5A (summary available)
         NADH-cytochrome b5 reductase 3 = CYB5R3 (summary available)

Unification Links: MOPED:P00167 , UniProt:P00167

Credits:
Created 06-Aug-2008 by Caspi R , SRI International


Gene Local Context (not to scale): ?

Gene local context diagram

Exons/Introns:

Schematic showing introns, exons and/or isoforms of FADS2


References

Cho99: Cho HP, Nakamura MT, Clarke SD (1999). "Cloning, expression, and nutritional regulation of the mammalian Delta-6 desaturase." J Biol Chem 274(1);471-7. PMID: 9867867

Ge03: Ge L, Gordon JS, Hsuan C, Stenn K, Prouty SM (2003). "Identification of the delta-6 desaturase of human sebaceous glands: expression and enzyme activity." J Invest Dermatol 120(5);707-14. PMID: 12713571

Lane03: Lane J, Mansel RE, Jiang WG (2003). "Expression of human delta-6-desaturase is associated with aggressiveness of human breast cancer." Int J Mol Med 12(2);253-7. PMID: 12851727

Marquardt00: Marquardt A, Stohr H, White K, Weber BH (2000). "cDNA cloning, genomic structure, and chromosomal localization of three members of the human fatty acid desaturase family." Genomics 66(2);175-83. PMID: 10860662

Nara02: Nara TY, He WS, Tang C, Clarke SD, Nakamura MT (2002). "The E-box like sterol regulatory element mediates the suppression of human Delta-6 desaturase gene by highly unsaturated fatty acids." Biochem Biophys Res Commun 296(1);111-7. PMID: 12147235

Stohr98: Stohr H, Marquardt A, Rivera A, Cooper PR, Nowak NJ, Shows TB, Gerhard DS, Weber BH (1998). "A gene map of the Best's vitelliform macular dystrophy region in chromosome 11q12-q13.1." Genome Res 8(1);48-56. PMID: 9445487

Tocher: Tocher DR, Leaver MJ, Hodgson PA "Recent advances in the biochemistry and molecular biology of fatty acyl desaturases." Prog Lipid Res 37(2-3);73-117. PMID: 9829122


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of HumanCyc: Genome Biology 6(1):1-17 2004
Page generated by SRI International Pathway Tools version 19.0 on Sun Aug 30, 2015, BIOCYC14A.