Eoxin C₄ (EXC₄), also known as 14,15- leukotriene C₄, 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 Dipeptidases are enzymes secreted by enterocytes into the small intestine. Dipeptidases hydrolyze bound pairs of amino acids, called dipeptides. Dipeptidases are secreted onto the brush border of the villi in the small intestine, where they cleave ...

, 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