Eoxin A₄ (EXA₄), also known as 14,15- leukotriene A₄, is an

eoxin Eoxins are proposed to be a family of proinflammatory eicosanoids (signaling compounds that regulate inflammatory and immune responses). They are produced by human eosinophils (a class of white blood cells), mast cells, the L1236 Reed–Sternberg ...

. Cells make eoxins by metabolizing arachidonic acid with a

15-lipoxygenase ALOX15 (also termed arachidonate 15-lipoxygenase, 15-lipoxygenase-1, 15-LO-1, 15-LOX-1) is, like other lipoxygenases, a seminal enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The ...

enzyme to form 15(''S'')-hydroperoxyeicosapentaenoic acid (i.e. 15(''S'')-HpETE). This product is then converted serially to EXA₄, EXC₄, EXD₄, and EXE₄ by LTC₄ synthase, an unidentified

gamma-glutamyltransferase Gamma-glutamyltransferase (also γ-glutamyltransferase, GGT, gamma-GT, gamma-glutamyl transpeptidase; ) is a transferase (a type of enzyme) that catalyzes the transfer of gamma- glutamyl functional groups from molecules such as glutathion ...

, and an unidentified dipeptidase, respectively, in a pathway which appears similar if not identical to the pathway which forms leukotreines, i.e. LTA₄, LTC₄, LTD₄, and LTE₄. This pathway is schematically shown as follows: EXA₄ is viewed as an intracellular-bound, short-lived intermediate which is rapidly metabolized to the downstream eoxins. The eoxins downstream of EXA₄ are secreted from their parent cells and, it is proposed but not yet proven, serve to regulate allergic responses and the development of certain cancers (see

s).

References

Eicosanoids {{biochemistry-stub