ALOX15 (also termed arachidonate 15-lipoxygenase, 15-lipoxygenase-1, 15-LO-1, 15-LOX-1) is, like other lipoxygenases, a seminal enzyme in the metabolism of polyunsaturated fatty acids to a wide range of physiologically and pathologically important products. In humans, it is encoded by the ALOX15 gene located on chromosome 17p13.3. This 11 kilobase pair gene consists of 14 exons and 13 introns coding for a 75 kiloDalton protein composed of 662 amino acids. 15-LO is to be distinguished from another human 15-lipoxygenase enzyme, ALOX15B (also termed 15-lipoxygenase-2).Orthologs of ALOX15, termed Alox15, are widely distributed in animal and plant species but commonly have different enzyme activities and make somewhat different products than ALOX15.