This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Synonyms: Δ5-eicosenoic acid biosynthesis
|Superclasses:||Biosynthesis → Fatty Acids and Lipids Biosynthesis → Fatty Acid Biosynthesis → Unusual Fatty Acid Biosynthesis|
Some taxa known to possess this pathway include : Limnanthes alba
Expected Taxonomic Range: Magnoliophyta
Oleic acid (18:1Δ9) is the most commonly found mono-unsaturated fatty acids in plant oils. However a number of novel mono-unsaturated fatty acid species are naturally accumulated in some plants. The seed oil of meadowfoam (Limnanthes alba) has high content of Δ5 unsaturated C20 and C22 fatty acids, with Δ5-eicosenoic acid (20:1Δ5) accounts for 60% of the total fatty acids. The high content of Δ5-eicosenoic acid makes the meadowfoam seed oil desirable for use in cosmetics, surfactants and lubricants.
The biosynthesis of Δ5-eicosenoic acid has novel features. The elongation step is catalyzed by a L. alba saturated fatty acid-specific FAE1. The elongation starts with palmitic acid (16:0) instead of stearic acid (18:0) or oleic acid (18:1). The latter two are commonly found to be the initial substrates used in very long chain fatty acids biosynthesis in most plant species. The Δ5 double bond is then introduced by an acyl-CoA desaturase which is rarely found in plants in that most plant desaturases use either acyl-ACP or fatty acids bound to glycerol lipids as substrates.
Cahoon00: Cahoon EB, Marillia EF, Stecca KL, Hall SE, Taylor DC, Kinney AJ (2000). "Production of fatty acid components of meadowfoam oil in somatic soybean embryos." Plant Physiol 124(1);243-51. PMID: 10982439
King07: King A, Nam JW, Han J, Hilliard J, Jaworski JG (2007). "Cuticular wax biosynthesis in petunia petals: cloning and characterization of an alcohol-acyltransferase that synthesizes wax-esters." Planta 226(2);381-94. PMID: 17323080
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