Arachidonate 12-lipoxygenase, 12R-type (ALOX12B)

Non-heme iron-containing dioxygenase that catalyzes the stereo-specific peroxidation of free and esterified polyunsaturated fatty acids generating a spectrum of bioactive lipid mediators. Mainly converts arachidonic acid to (12R)- hydroperoxyeicosatetraenoic acid/(12R)-HPETE and small stereoisomers.

From the skin, acts upstream of ALOXE3 on the lineolate moiety of esterified omega-hydroxyacyl-sphingosine (EOS) ceramides to create an epoxy-ketone derivative, a vital step in the conjugation of omega-hydroxyceramide to membrane proteins. Therefore plays a crucial role in the synthesis of corneocytes lipid envelope and the institution of the skin barrier to water loss.