MetaCyc Reaction:

Superclasses: Reactions Classified By Conversion TypeSimple ReactionsChemical Reactions
Reactions Classified By SubstrateSmall-Molecule Reactions

EC Number:

Enzymes and Genes:

Arabidopsis thaliana col: acyl-lipid ω-3 desaturase (endoplasmic reticulum)Inferred from experiment: FAD3

In Pathway: phospholipid desaturation

Note that this reaction equation differs from the official Enzyme Commission reaction equation for this EC number, which can be found here .

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the direction in which it was curated.

Most BioCyc compounds have been protonated to a reference pH value of 7.3. Please see the PGDB Concepts Guide for more information.

Mass balance status: Balanced.

Enzyme Commission Primary Name: acyl-lipid ω-3 desaturase (cytochrome b5)

Standard Gibbs Free Energy (ΔrG in kcal/mol): -73.37756Inferred by computational analysis [Latendresse13]

Enzyme Commission Summary:
This microsomal enzyme introduces a cis double bond three carbons from the methyl end of a fatty acid incorporated into a glycerlipid. 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 [Sakuradani05]. cf. EC, sn-2 acyl-lipid ω-3 desaturase (ferredoxin).

Citations: [Browse93, Amikam77]

Gene-Reaction Schematic

Gene-Reaction Schematic

Relationship Links: BRENDA:EC:, ENZYME:EC:, IUBMB-ExplorEnz:EC:


Amikam77: Amikam S, Peleg H, Lemer J, Riss E (1977). "Myopotential inhibition of a bipolar pacemaker caused by electrode insulation defect." Br Heart J 39(11);1279-81. PMID: 145229

Browse93: Browse J, McConn M, James D, Miquel M (1993). "Mutants of Arabidopsis deficient in the synthesis of alpha-linolenate. Biochemical and genetic characterization of the endoplasmic reticulum linoleoyl desaturase." J Biol Chem 1993;268(22);16345-51. PMID: 8102138

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Sakuradani05: Sakuradani E, Abe T, Iguchi K, Shimizu S (2005). "A novel fungal omega3-desaturase with wide substrate specificity from arachidonic acid-producing Mortierella alpina 1S-4." Appl Microbiol Biotechnol 66(6);648-54. PMID: 15538555

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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