KEGG   ENZYME: 1.14.19.12
Entry
EC 1.14.19.12               Enzyme                                 

Name
acyl-lipid omega-(9-4) desaturase;
acyl-lipid omega-13 desaturase;
acyl-lipid 7-desaturase (ambiguous)
Class
Oxidoreductases;
Acting on paired donors, with incorporation or reduction of molecular oxygen;
With oxidation of a pair of donors resulting in the reduction of O2 to two molecules of water
Sysname
acyl-[glycerolipid],ferrocytochrome b5:oxygen oxidoreductase [omega(9-4),omega(9-5) cis-dehydrogenating]
Reaction(IUBMB)
(1) linoleoyl-[glycerolipid] + 2 ferrocytochrome b5 + O2 + 2 H+ = pinolenoyl-[glycerolipid] + 2 ferricytochrome b5 + 2 H2O [RN:R11644];
(2) alpha-linolenoyl-[glycerolipid] + 2 ferrocytochrome b5 + O2 + 2 H+ = coniferonoyl-[glycerolipid] + 2 ferricytochrome b5 + 2 H2O [RN:R11645]
Reaction(KEGG)
R11644 R11645
Substrate
linoleoyl-[glycerolipid] [CPD:C21529];
ferrocytochrome b5 [CPD:C00999];
O2 [CPD:C00007];
H+ [CPD:C00080];
alpha-linolenoyl-[glycerolipid] [CPD:C21531]
Product
pinolenoyl-[glycerolipid] [CPD:C21530];
ferricytochrome b5 [CPD:C00996];
H2O [CPD:C00001];
coniferonoyl-[glycerolipid] [CPD:C21532]
Comment
The enzyme, characterized from the green alga Chlamydomonas reinhardtii, is a front-end desaturase that introduces a cis double bond in omega9 unsaturated C18 or C20 fatty acids incorporated into lipids, at a position 4 carbon atoms from the existing omega9 bond, towards the carboxy end of the fatty acid (at the omega13 position). When acting on 20:2Delta(11,14) and 20:3Delta(11,14,17) substrates it introduces the new double bond between carbons 7 and 8. The enzyme contains a cytochrome b5 domain that acts as the direct electron donor for the active site of the desaturase.
History
EC 1.14.19.12 created 2015
Orthology
K21706  acyl-lipid omega-(9-4) desaturase
Genes
CRE: CHLREDRAFT_182572
Reference
1  [PMID:16267098]
  Authors
Kajikawa M, Yamato KT, Kohzu Y, Shoji S, Matsui K, Tanaka Y, Sakai Y, Fukuzawa H
  Title
A front-end desaturase from Chlamydomonas reinhardtii produces pinolenic and coniferonic acids by omega13 desaturation in methylotrophic yeast and tobacco.
  Journal
Plant Cell Physiol 47:64-73 (2006)
DOI:10.1093/pcp/pci224
  Sequence
Other DBs
ExplorEnz - The Enzyme Database: 1.14.19.12
IUBMB Enzyme Nomenclature: 1.14.19.12
ExPASy - ENZYME nomenclature database: 1.14.19.12
BRENDA, the Enzyme Database: 1.14.19.12

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