EC Explorer

1.14.19.25

acyl-lipid ω-3 desaturase (cytochrome b₅)

a linoleoyl-[glycerolipid] + 2 ferrocytochrome b₅ + O₂ + 2 H⁺ = an α-linolenoyl-[glycerolipid] + 2 ferricytochrome b₅ + 2 H₂O

FAD3

(9Z,12Z)-octadeca-9,12-dienoyl-[glycerolipid],ferrocytochrome b₅:oxygen oxidoreductase (15,16 cis-dehydrogenating)

This microsomal enzyme introduces a cis double bond three carbons away from the methyl end of a fatty acid incorporated into a glycerolipid. The distance from the carboxylic acid end of the molecule does not have an effect. The plant enzyme acts on carbon 15 of linoleoyl groups incorporated into both the sn-1 and sn-2 positions of the glycerol backbone of phosphatidylcholine and other phospholipids, converting them into α-linolenoyl groups. The enzyme from the fungus Mortierella alpina acts on γ-linolenoyl and arachidonoyl groups, converting them into stearidonoyl and icosapentaenoyl groups, respectively [3]. cf. EC 1.14.19.35, sn-2 acyl-lipid ω-3 desaturase (ferredoxin).

created 2015