FADS2

PMID:9867867

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
BRITE hierarchy

acyl-CoA,ferrocytochrome b5:oxygen oxidoreductase (6,7 cis-dehydrogenating)

(1) linoleoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ = gamma-linolenoyl-CoA + 2 ferricytochrome b5 + 2 H2O [RN:R03814];
(2) alpha-linolenoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ = stearidonoyl-CoA + 2 ferricytochrome b5 + 2 H2O [RN:R07933]

R03814 R07933;
(other) R11110 R11111 R12167 R12168 R12170 R12171 R12172
Reaction

linoleoyl-CoA [CPD:C02050];
ferrocytochrome b5 [CPD:C00999];
O2 [CPD:C00007];
H+ [CPD:C00080];
alpha-linolenoyl-CoA [CPD:C16162]

An iron protein. The enzyme introduces a cis double bond at carbon 6 of acyl-CoAs. It is a front-end desaturase, introducing the new double bond between a pre-existing double bond and the carboxyl-end of the fatty acid. The human enzyme has a broad substrate range. It also acts on palmitoyl-CoA, generating sapienoyl-CoA [4], and on (9Z,12Z,15Z,18Z,21Z)-tetracosa-9,12,15,18,21-pentaenoyl-CoA, converting it to (6Z,9Z,12Z,15Z,18Z,21Z)-tetracosa-6,9,12,15,18,21-hexaenoyl-CoA as part of a pathway that produces docosahexaenoate [3]. The enzyme contains a cytochrome b5 domain that is assumed to act in vivo as the electron donor to the active site of the desaturase.

EC 1.14.19.3 created 1986 as EC 1.14.99.25, transferred 2000 to EC 1.14.19.3, modified 2015