| Synonyms |
CrDELTA4FAD, DELTA4 desaturase, DELTA4 fatty acid desaturase, DELTA4-desaturase, DELTA4-fatty acid desaturase, DELTA4Fad, Egd4p, FADS2, MGDG-specific DELTA4-desaturase, monogalactosyldiacylglycerol-specific DELTA4-desaturase, Old4p, PlDES1, PsD4De |
| Comments |
The enzymes from several algae introduce a cis double bond at the 4-position in 22-carbon polyunsaturated fatty acids that contain a ¦¤7 double bond. The enzyme from the fresh water alga Chlamydomonas reinhardtii acts on the 16 carbon fatty acid (7Z,10Z,13Z)-hexadeca-7,10,13-trienoate [5]. The enzyme contains an N-terminal cytochrome b5 domain that acts as the direct electron donor to the active site of the desaturase, and does not require an external cytochrome. |
| Reactions |
(1) A (7Z,10Z,13Z,16Z,19Z)-docosa-7,10,13,16,19-pentaenoyl-[glycerolipid] + 2 ferrocytochrome b5 + O(2) + 2 H(+) = a (4Z,7Z,10Z,13Z,16Z,19Z)- docosa-4,7,10,13,16,19-hexaenoyl-[glycerolipid] + 2 ferricytochrome b5 + 2 H(2)O. (2) A (7Z,10Z,13Z,16Z)-docosa-7,10,13,16-tetraenoyl-[glycerolipid] + 2 ferrocytochrome b5 + O(2) + 2 H(+) = a (4Z,7Z,10Z,13Z,16Z)-docosa- 4,7,10,13,16-pentaenoyl-[glycerolipid] + 2 ferricytochrome b5 + 2 H(2)O. |
