Figure 1.

Proposed model for the biosynthesis of the 9- and 13-lipoxygenase derived cyclopentenones 10-oxo-11-phytoenoic acid (10-OPEA), 10-oxo-11,15-phytodienoic acid (10-OPDA), and 12-oxo-10,15-phytodienoic acid (12-OPDA) and their respective derivatives (modified from Christensen et al.¹³). Black dashed arrows indicate the presence of predicted enzyme activities requiring future confirmation. Abbreviations are as follows: lipoxygenase (LOX), allene oxide synthase (AOS), linolenic acid (18:3), linoleic acid (18:2), 9-hydroperoxy-10,12-octadecadienoic acid (9-HPOD), 9-hydroperoxy-10,12,15- octadecatrienoic acid (9-HPOT), 13-hydroperoxy-10,12,15-octadecatrienoic acid (13-HPOT); 9,10-epoxyoctadecatrienoic acid (9,10-EOT); 9,10-epoxyoctadecadienoic acid (9,10-EOD); 12,13-epoxyoctadecatrienoic acid (12,13-EOT); 3-oxo-2-(2′-pentenyl)-cyclopentane-1-octanoic acid (OPC-8:0), and hexanoic acid (OPC-6:0), DA⁰-4:1, (4-[(1,5)-2-oxo-5-pentylcyclopent-3-ene-1-yl] hexanoic acid; DA⁰-4:0, 4-[(1,5)-2-oxo-5-pentylcyclopent-3-ene-1-yl] butanoic acid; DA⁰-2:0, (2-[(1, 5)-2-oxo-5-pentylcyclopent-3-ene-1-yl] acetic acid; DA¹-4:0, 4-[(1,5)-2-oxo-5-[(2)-pent-2-en-1-yl]clyclopentyl] butanoic acid; DA¹-2:0, 2-[(1,5)-2-oxo-5-[(2)-pent-2-en-1-yl]clyclopentyl] acetic acid.