Cyclooxygenase and lipoxygenase pathways via fatty acid substrate competition

The cyclooxygenase (COX) and lipoxygenase (LOX) pathways are the primary enzymatic systems responsible for converting polyunsaturated fatty acids (PUFAs) into eicosanoids, which are critical signaling molecules in inflammation and immunity (StatPearls, Eicosanoids, 2023). Substrate competition involves the simultaneous presence of different PUFAs, such as arachidonic acid (AA) and eicosapentaenoic acid (EPA), which compete for the catalytic sites of COX and LOX enzymes (PubMed, PMID: 22591890). While AA-derived eicosanoids are generally pro-inflammatory, such as prostaglandin E2 and leukotriene B4, EPA-derived analogs are often less potent or possess anti-inflammatory properties (NIH, Omega-3 Fatty Acids Fact Sheet). This mechanism is therapeutically exploited through dietary supplementation or pharmacological intervention to shift the eicosanoid profile toward a less inflammatory state. Consequently, this pathway competition plays a significant role in the management of cardiovascular disease, asthma, and chronic inflammatory disorders (Nature Reviews Drug Discovery, 2003). Understanding these pathways allows for the development of drugs that specifically modulate lipid mediator production to treat systemic inflammation.

Other names

Eicosanoid biosynthetic pathwayArachidonic acid metabolismPUFA substrate competitionCOX/LOX pathways

Competitive inhibition of enzymes (COX and LOX) by alternative fatty acid substrates (e.g., EPA/DHA competing with Arachidonic Acid) to shift eicosanoid production toward less inflammatory profiles.