as linoleic acid and arachidonic acid. Lipoxygenases (LOXs) catalyze the oxygenation of polyunsaturated fatty acids such as arachidonic acid and linoleic acid. The oxygenated lipids initiate subsequent biological reactions, activate cellular signaling mechanisms through specific cell surface receptors, or are further metabolized into potent lipid mediators. LOX can be found not only in mammals, but also in plants. Historically, biochemical characterizations have been performed mainly on soybean LOX isoforms. While the overall structure of mammalian LOX enzymes seems to be similar, each isoform has unique properties, such as substrate specificity. 
LOX enzymes require a lag period for the activation of enzymes from an inactive ferrous form to an active ferric form by either molecular oxygen or lipid hydroperoxides. LOX enzymatic activity can be inhibited by phenolic antioxidants such as nordihydroguaiaretic acid and caffeic acid, suggesting a beneficial role of dietary polyphenol intake. The physiological roles of LOX enzymes have been studied extensively, due to the close link between them and various diseases. Apparently, the best characterized example includes the relation between 5-LOX and asthma, because cysteinyl leukotriene receptor 1, a GPCR activated by leukotrienes produced by 5-LOX, is widely expressed on bronchiolar smooth muscle cells. Genetically, both ALOX12B and ALOXE3 play a critical role in the development of ichthyosis through TEWL. In humans, some mutations in ALOX12 are found in tumor cells, suggesting this isoform might have anti-tumor effect. An increased expression of LOX enzymes in response to Th2 cytokines has been well established.


1.Mashima R, et al. Redox Biol. 2015;6:297–310.