EC |
1.14.19.30 |
Accepted name: |
acyl-lipid (8-3)-desaturase |
Reaction: |
(1) an (8Z,11Z,14Z)-icosa-8,11,14-trienoyl-[glycerolipid] + 2 ferrocytochrome b5 + O2 + 2 H+ = a (5Z,8Z,11Z,14Z)-icosatetra-5,8,11,14-tetraenoyl-[glycerolipid] + 2 ferricytochrome b5 + 2 H2O (2) an (8Z,11Z,14Z,17Z)-icosa-8,11,14,17-tetraenoyl-[glycerolipid] + 2 ferrocytochrome b5 + O2 + 2 H+ = a (5Z,8Z,11Z,14Z,17Z)-icosa-5,8,11,14,17-pentaenoyl-[glycerolipid] + 2 ferricytochrome b5 + 2 H2O |
Glossary: |
(8Z,11Z,14Z)-icosa-8,11,14-trienoate = di-homo-γ-linolenate
(5Z,8Z,11Z,14Z)-icosa-8,11,14-trienoate = arachidonate |
Other name(s): |
acyl-lipid 5-desaturase; Δ5-fatty-acid desaturase; DES5 (gene name); D5des (gene name); FADS1 |
Systematic name: |
Δ8 acyl-lipid,ferrocytochrome b5:oxygen oxidoreductase (5,6 cis-dehydrogenating) |
Comments: |
The enzyme, which has been characterized from multiple organisms including the moss Physcomitrella patens, the marine microalga Rebecca salina, and the filamentous fungus Mortierella alpina, introduces a cis double bond at the 5-position in 20-carbon polyunsaturated fatty acids incorporated in a glycerolipid that contain a Δ8 double bond. The enzyme contains a cytochrome b5 domain that acts as the direct electron donor to the active site of the desaturase, and does not require an external cytochrome. |
References: |
1. |
Michaelson, L.V., Lazarus, C.M., Griffiths, G., Napier, J.A. and Stobart, A.K. Isolation of a Δ5-fatty acid desaturase gene from Mortierella alpina. J. Biol. Chem. 273 (1998) 19055–19059. [PMID: 9668087] |
2. |
Kaewsuwan, S., Cahoon, E.B., Perroud, P.F., Wiwat, C., Panvisavas, N., Quatrano, R.S., Cove, D.J. and Bunyapraphatsara, N. Identification and functional characterization of the moss Physcomitrella patens Δ5-desaturase gene involved in arachidonic and eicosapentaenoic acid biosynthesis. J. Biol. Chem. 281 (2006) 21988–21997. [PMID: 16728405] |
3. |
Zhou, X.R., Robert, S.S., Petrie, J.R., Frampton, D.M., Mansour, M.P., Blackburn, S.I., Nichols, P.D., Green, A.G. and Singh, S.P. Isolation and characterization of genes from the marine microalga Pavlova salina encoding three front-end desaturases involved in docosahexaenoic acid biosynthesis. Phytochemistry 68 (2007) 785–796. [PMID: 17291553] |
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[EC 1.14.19.30 created 2015] |
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