ALOX15B

Description

The ALOX15B (arachidonate 15-lipoxygenase type B) is a protein-coding gene located on chromosome 17.

Arachidonate 15-lipoxygenase type II is an enzyme that in humans is encoded by the ALOX15B gene. ALOX15B, also known as 15-lipoxygenase-2 (15-LO-2 or 15-LOX-2), is distinguished from its related oxygenase, ALOX15 or 15-lipoxygenase-1.

== Function == This gene encodes a member of the lipoxygenase family of structurally related nonheme iron dioxygenases involved in the production of fatty acid hydroperoxides. 15-LOX-2 has 38-39% amino acid sequence identity to human 15-LOX-1 and 12-lipoxygenase and 44% amino acid sequence identity to human 5-lipoxygenase. 15-LOX-2 converts arachidonic acid almost exclusively to the S stereoisomer of 15-Hydroperoxyicosatetraenoic acid which is commonly reduced to the S stereoisomer 15-Hydroxyeicosatetraenoic acid by ubiquitous cellular peroxidases; it metabolizes linoleic acid less effectively, converting this fatty acid to the S stereoisomer of 13-hydroperoxyoctadecadienoic acid which is likewise rapidly reduced to the S stereoisomer of 13-Hydroxyoctadecadienoic acid. The ALOX15B gene is located in a cluster of related genes and a pseudogene that spans approximately 100 kilobases on the short arm of chromosome 17. Alternatively spliced transcript variants encoding different isoforms have been described.

== See also == Arachidonate 15-lipoxygenase 15-hydroxyicosatetraenoic acid ALOX15

== References ==

== External links == Human ALOX15B genome location and ALOX15B gene details page in the UCSC Genome Browser.

[Isoform A]: 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 (PubMed:9177185, PubMed:10625675, PubMed:12704195, PubMed:17493578, PubMed:18311922, PubMed:24282679, PubMed:10542053, PubMed:24497644, PubMed:32404334) (Probable). It inserts peroxyl groups at C15 of arachidonate ((5Z,8Z,11Z,14Z)-eicosatetraenoate) producing (15S)-hydroperoxyeicosatetraenoate/(15S)-HPETE (PubMed:17493578, PubMed:12704195, PubMed:24282679, PubMed:9177185, PubMed:11956198, PubMed:10625675, PubMed:24497644) (Probable). It also peroxidizes linoleate ((9Z,12Z)-octadecadienoate) to 13- hydroperoxyoctadecadienoate/13-HPODE (Probable) (PubMed:10542053, PubMed:27435673). It oxygenates arachidonyl derivatives such as 2- arachidonoylglycerol (2-AG) leading to the production and extracellular release of 15-hydroxyeicosatetraenoyl glycerol (15-HETE-G) that acts as a peroxisome proliferator-activated receptor alpha agonist (PubMed:18311922, PubMed:17493578, PubMed:11956198). It has the ability to efficiently class-switch ALOX5 pro-inflammatory mediators into anti- inflammatory intermediates (PubMed:27145229). It participates in the sequential oxidations of DHA ((4Z,7Z,10Z,13Z,16Z,19Z)-docosahexaenoate) to generate specialized pro-resolving mediators (SPMs) resolvin D5 ((7S,17S)-diHPDHA), which can actively down-regulate the immune response and have anti-aggregation properties with platelets (PubMed:32404334). In addition to free PUFAs hydrolyzed from phospholipids, it directly oxidizes PUFAs esterified to membrane-bound phospholipids (PubMed:27435673). It has no detectable 8S-lipoxygenase activity on arachidonate but reacts with (8S)-HPETE to produce (8S,15S)-diHPETE (Probable). It may regulate progression through the cell cycle and cell proliferation (PubMed:12704195, PubMed:11839751). It may also regulate cytokine secretion by macrophages and therefore play a role in the immune response (PubMed:18067895). It may also regulate macrophage differentiation into proatherogenic foam cells (PubMed:22912809).

ALOX15B is also known as 15-LOX-2.

Associated Diseases

WES Whole Exome Sequencing