ENZYME

ENZYME entry: EC 1.14.19.25

Accepted Name

Acyl-lipid omega-3 desaturase (cytochrome b5).

Reaction catalysed

A linoleoyl-[glycerolipid] + 2 ferrocytochrome b5 + O(2) + 2 H(+) <=> an alpha-linolenoyl-[glycerolipid] + ferricytochrome b5 + 2 H(2)O

Comment(s)

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 alpha-linolenoyl groups.
The enzyme from the fungus Mortierella alpina acts on gamma- linolenoyl and arachidonoyl groups, converting them into stearidonoyl and icosapentaenoyl groups, respectively.
Cf. EC 1.14.19.35.

Cross-references

BRENDA

EC2PDB

ExplorEnz

PRIAM enzyme-specific profiles

KEGG Ligand Database for Enzyme Nomenclature

IUBMB Enzyme Nomenclature