Non-heme iron-containing lipoxygenase which is atypical in that it displays a prominent hydroperoxide isomerase activity and a reduced lipoxygenases activity. The hydroperoxide isomerase activity catalyzes the isomerization of hydroperoxides, derived from arachidonic and linoleic acid by ALOX12B, into hepoxilin-type epoxyalcohols and ketones. In presence of oxygen, oxygenates polyunsaturated fatty acids, including arachidonic acid, to produce fatty acid hydroperoxides. In the skin, acts downstream of ALOX12B on the linoleate moiety of esterified omega-hydroxyacyl-sphingosine (EOS) ceramides to produce an epoxy-ketone derivative, a crucial step in the conjugation of omega-hydroxyceramide to membrane proteins. Therefore plays a crucial role in the synthesis of corneocytes lipid envelope and the establishment of the skin barrier to water loss. In parallel, it may have a signaling function in barrier formation through the production of hepoxilins metabolites (By similarity). Also plays a role in adipocyte differentiation through hepoxilin A3 and hepoxilin B3 production which in turn activate PPARG (By similarity). Through the production of hepoxilins in the spinal cord, it may regulate inflammatory tactile allodynia (PubMed:23382512). a hydroperoxyeicosatetraenoate = a hydroxy-epoxy-eicosatetraenoate a hydroperoxyeicosatetraenoate = an oxoeicosatetraenoate + H2O (12R)-hydroperoxy-(5Z,8Z,10E,14Z)-eicosatetraenoate = (8R)-hydroxy-(11R,12R)-epoxy-(5Z,9E,14Z)-eicosatrienoate (12S)-hydroperoxy-(5Z,8Z,10E,14Z)-eicosatetraenoate = (8R)-hydroxy-(11S,12S)-epoxy-(5Z,9E,14Z)-eicosatrienoate (12S)-hydroperoxy-(5Z,8Z,10E,14Z)-eicosatetraenoate = (10R)-hydroxy-(11S,12S)-epoxy-(5Z,8Z,14Z)-eicosatrienoate (15S)-hydroperoxy-(5Z,8Z,11Z,13E)-eicosatetraenoate = (13R)-hydroxy-(14S,15S)-epoxy-(5Z,8Z,11Z)-eicosatrienoate (5S)-hydroperoxy-(6E,8Z,11Z,14Z)-eicosatetraenoate = 7R-hydroxy-5S,6S-epoxy-(8Z,11Z,14Z)-eicosatrienoate (13S)-hydroperoxy-(9Z,11E)-octadecadienoate = 11-hydroxy-(12S,13S)-epoxy-(9Z)-octadecenoate N-[omega-(9R)-hydroperoxy-(10E,12Z)-octadecadienoyloxy]acyl-beta-D-glucosyl-(1<->1)-octadecasphing-4E-enine = N-[omega-(9R,10R)-epoxy-(13R)-hydroxy-(11E)-octadecadienoyloxy]acyl-beta-D-glucosyl-(1<->1)-octadecasphing-4E-enine N-acyl (9R)-hydroperoxy-(10E,12Z)-octadecadienoate octadecasphing-4E-enine = N-acyl-(9R,10R)-epoxy-(13R)-hydroxy-(11E)-octadecenoate (4E)-octadecasphin-4-enine (12R)-hydroperoxy-(5Z,8Z,10E,14Z)-eicosatetraenoate = 12-oxo-(5Z,8Z,10E,14Z)-eicosatetraenoate + H2O (12S)-hydroperoxy-(5Z,8Z,10E,14Z)-eicosatetraenoate = 12-oxo-(5Z,8Z,10E,14Z)-eicosatetraenoate + H2O (15S)-hydroperoxy-(5Z,8Z,11Z,13E)-eicosatetraenoate = 15-oxo-(5Z,8Z,11Z,13E)-eicosatetraenoate + H2O (13S)-hydroperoxy-(9Z,11E)-octadecadienoate = 13-oxo-(9Z,11E)-octadecadienoate + H2O (8S)-hydroperoxy-(5Z,9E,11Z,14Z)-eicosatetraenoate = (10R)-hydroxy-(8S,9S)-epoxy-(5Z,11Z,14Z)-eicosatrienoate (8R)-hydroperoxy-(5Z,9E,11Z,14Z)-eicosatetraenoate = 8-oxo-(5Z,9E,11Z,14Z)-eicosatetraenoate + H2O (8S)-hydroperoxy-(5Z,9E,11Z,14Z)-eicosatetraenoate = 8-oxo-(5Z,9E,11Z,14Z)-eicosatetraenoate + H2O Binds 1 Fe cation per subunit. Lipid metabolism; hydroperoxy eicosatetraenoic acid biosynthesis. Lipid metabolism; sphingolipid metabolism. Belongs to the lipoxygenase family. about water - Issue 153 of September 2013