ID   1.14.19.31
DE   acyl-lipid (7-3)-desaturase.
AN   acyl-lipid 4-desaturase.
CA   (1) a (7Z,10Z,13Z,16Z,19Z)-docosapentaenoyl-containing glycerolipid +
CA   2 Fe(II)-[cytochrome b5] + 2 H(+) + O2 = a (4Z,7Z,10Z,13Z,16Z,19Z)-
CA   docosahexaenoyl-containing glycerolipid + 2 Fe(III)-[cytochrome b5] +
CA   2 H2O.
CA   (2) a (7Z,10Z,13Z,16Z)-docosatetraenoyl-containing glycerolipid +
CA   2 Fe(II)-[cytochrome b5] + 2 H(+) + O2 = a (4Z,7Z,10Z,13Z,16Z)-
CA   docosapentaenoyl-containing glycerolipid + 2 Fe(III)-[cytochrome b5] +
CA   2 H2O.
CC   -!- The enzymes from several algae introduce a cis double bond at the
CC       4-position in 22-carbon polyunsaturated fatty acids that contain a
CC       Delta(7) double bond.
CC   -!- The enzyme from the fresh water alga Chlamydomonas reinhardtii acts
CC       on the 16 carbon fatty acid (7Z,10Z,13Z)-hexadeca-7,10,13-trienoate.
CC   -!- The enzyme contains an N-terminal cytochrome b5 domain that acts as
CC       the direct electron donor to the active site of the desaturase,
CC       and does not require an external cytochrome.
DR   I2CYZ4, D4FAD_CHLRE;  Q6VPV2, D4FAD_DIALT;  Q6WNG7, D4FAD_EUGGR;
DR   A0PJ29, D4FAD_REBSA;  Q8S3C0, D4FAD_THRSP;
//