Isoform A:
Non-heme iron-containing dioxygenase that catalyzes the stereo-specific peroxidation of free and esterified polyunsaturated fatty acids (PUFAs) generating a spectrum of bioactive lipid mediators. Converts arachidonic acid to 15S-hydroperoxyeicosatetraenoic acid/(15S)-HPETE (Probable). Also acts on linoleic acid to produce 13-hydroxyoctadecadienoic acid/13-HPODE (Probable. Oxygenates arachidonyl derivatives such as 2-arachidonoylglycerol (2-AG) leading to the production and extracellular release of 15-hydroxyeicosatetraenoic acid glyceryl ester (15-HETE-G) that acts as a peroxisome proliferator-activated receptor alpha agonist . Has the ability to efficiently class-switch ALOX5 pro-inflammatory mediators into anti-inflammatory intermediates . In addition to metabolize free PUFAs hydrolyzed from phospholipids, directly oxidizes PUFAs esterified to membrane-bound phospholipids . Has no detectable 8S-lipoxygenase activity on arachidonate but reacts with (8S)-HPETE to produce (8S,15S)-diHPETE (Probable). May regulate progression through the cell cycle and cell proliferation. May also regulate cytokine secretion by macrophages and therefore play a role in the immune response. May also regulate macrophage differentiation into proatherogenic foam cells .