ID   1.14.19.12
DE   acyl-lipid omega-(9-4) desaturase.
AN   acyl-lipid 7-desaturase.
AN   acyl-lipid omega-13 desaturase.
CA   (1) a (9Z,12Z)-octadecadienoyl-containing glycerolipid + 2 Fe(II)-
CA   [cytochrome b5] + 2 H(+) + O2 = a (5Z,9Z,12Z)-octadecatrienoyl-containing
CA   glycerolipid + 2 Fe(III)-[cytochrome b5] + 2 H2O.
CA   (2) (9Z,12Z,15Z)-octadecatrienoyl-containing glycerolipid + 2 Fe(II)-
CA   [cytochrome b5] + 2 H(+) + O2 = a (5Z,9Z,12Z,15Z)-octadecatetraenoyl-
CA   containing glycerolipid + 2 Fe(III)-[cytochrome b5] + 2 H2O.
CC   -!- The enzyme, characterized from the green alga Chlamydomonas
CC       reinhardtii, is a front-end desaturase that introduces a cis double
CC       bond in omega(9) unsaturated C18 or C20 fatty acids incorporated into
CC       lipids, at a position 4 carbon atoms from the existing omega(9) bond,
CC       toward the carboxy end of the fatty acid (at the omega(13) position).
CC   -!- When acting on 20:2Delta(11,14) and 20:3Delta(11,14,17) substrates it
CC       introduces the new double bond between carbons 7 and 8.
CC   -!- The enzyme contains a cytochrome b5 domain that acts as the direct
CC       electron donor for the active site of the desaturase.
DR   Q2HWK7, DES_CHLRE  ;
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