MK-886 sodium salt, also designated L-663,536, is a potent and selective inhibitor of 5-lipoxygenase-activating protein (FLAP). FLAP is an arachidonic acid binding protein that is critical in the biosynthesis of leukotrienes. Inhibitors of FLAP prevent translocation of 5-lipoxygenase from the cytosol to the membrane and inhibit 5-lipoxygenase (5-LO) activation. MK-886 binds to FLAP with high affinity and prevents the activation of 5-LO, thus inhibiting leukotriene biosynthesis: 2.5 nM in intact leukocytes; 1.1 µM in whole blood. MK-886 sodium salt is an inhibitor of Cox-1, PGE Synthase and PPARα.