Description
Leukotriene A
4 (LTA
4) is synthesized in mast cells, eosinophils, and neutrophils from arachidonic acid by 5-
lipoxygenase (5-
LO), which exhibits both lipoxygenase and LTA
4 synthase activities. LTA
4 is rapidly metabolized by LTA
4 hydrolase or LTC
4 synthase to LTB
4 or LTC
4, respectively. LTA
4, from leukocytes, is known to undergo transcellular metabolism in platelets, erythrocytes, and endothelial cells. Further metabolism of LTA
4 by 15-
LO leads to lipoxin biosynthesis. LTA
4 as a free acid is highly unstable. The methyl ester is stable and can be readily hydrolyzed to the free acid as needed.