General Background Lipoxins belong to the eicosanoid family, have a distinct conjugated tetraene structure and are generated from : ARACHIDONIC_ACID during inflammation. They consist of two distinct isomers, : CPD66-51 (LXA4) and : CPD66-56 (LXB4). These lipid derived mediators play an important role in modulating the inflammatory response. : CPD66-51 "Lipoxin A4" (LXA4) dampens the immune response by inhibiting leukocyte chemotaxis, transmigration and adhesion . It also promotes the resolution phase of inflammation by enhancing phagocytosis of apoptotic leukocytes by macrophages . These activities are brought about through the G protein-coupled receptor ALX . About this Pathway This de novo pathway produces the 15S series of lipoixns. There are two routes of lipoxin biosynthesis in humans. One pathway occurs during platelet-leukocyte interactions. When platelet-leukocyte adhesion occurs, leukocyte 5-lipoxygenase converts : ARACHIDONIC_ACID to : CPD-8892 (LTA4) . The released LTA4 is then transformed by adherent platelets to LXA4 and LXB4 via the LX synthase activity of 12-lipoxygenase . In addition to the lipoxygenase-initiated biosynthesis of lipoxins, a novel aspirin-triggered route involving COX-2 and the 15R series of lipoxins is also present, see : PWY66-393. The biosynthesis of lipoxins leads to a concommitant reduction in leukotriene formation. Another biosynthetic route occurs at mucosal surfaces where : HS08621-MONOMER catalyzes the conversion of arachidonate to : CPD66-55 . : CPD66-55 is taken up by leukocytes and converted to lipoxins. Alveolar macrophages can also synthesize lipoxins via this route

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ALOX12 , ALOX5 , ALOX15 ,