Reaction: (1) a linoleoyl-[glycerolipid] + 2 ferrocytochrome b5 + O2 + 2 H+ = an α-eleostearoyl-[glycerolipid] + 2 ferricytochrome b5 + 2 H2O
(2) a γ-linolenoyl-[glycerolipid] + 2 ferrocytochrome b5 + O2 + 2 H+ = an α-parinaroyl-[glycerolipid] + 2 ferricytochrome b5 + 2 H2O
Glossary: α-eleostearate = (9Z,11E,13E)-octadeca-9,11,13-trienoate
α-parinarate = (9Z,11E,13E,15Z)-octadeca-9,11,13,15-tetraenoate
γ-linolenic acid = (6Z,9Z,12Z)-octadeca-6,9,12-trienoic acid
linoleic acid = (9Z,12Z)-octadeca-9,12-dienoic acid
Other name(s): fatty acid Δ12-conjugase (ambiguous); FADX (gene name)
Systematic name: Δ12 acyl-lipid,ferrocytochrome-b5:oxygen 11,14 allylic oxidase (11E,13E-forming)
Comments: The enzyme, characterized from the plants Impatiens balsamina, Momordica charantia (bitter gourd) and Vernicia fordii (tung tree), converts a single cis double bond at carbon 12 to two conjugated trans bonds at positions 11 and 13. The enzyme from Vernicia fordii can also act as a 12(E) desaturase when acting on the monounsaturated fatty acids oleate and palmitoleate. cf. EC 1.14.19.16, linoleoyl-lipid Δ12 conjugase (11E,13Z-forming).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Cahoon, E.B., Carlson, T.J., Ripp, K.G., Schweiger, B.J., Cook, G.A., Hall, S.E. and Kinney, A.J. Biosynthetic origin of conjugated double bonds: production of fatty acid components of high-value drying oils in transgenic soybean embryos. Proc. Natl. Acad. Sci. USA 96 (1999) 12935-12940. [PMID: 10536026]
2. Dyer, J.M., Chapital, D.C., Kuan, J.C., Mullen, R.T., Turner, C., McKeon, T.A. and Pepperman, A.B. Molecular analysis of a bifunctional fatty acid conjugase/desaturase from tung. Implications for the evolution of plant fatty acid diversity. Plant Physiol. 130 (2002) 2027-2038. [PMID: 12481086]