Description
Leukotriene A
4 (LTA
4) hydrolase/aminopeptidase is a bifunctional zinc metalloenzyme that both catalyzes the synthesis of LTB
4 from LTA4 and cleaves the chemotactic peptide Pro-Gly-Pro. SC-57461A is a potent, orally active inhibitor of LTA
4 hydrolase that blocks ionophore-stimulated LTB
4 synthesis in whole blood (IC
50 = 49 nM). It blocks both the hydrolase and aminopeptidase activity
in vitro. SC-57461A is without effect against other enzymes of the arachidonic acid cascade, including 5-lipoxygenase, LTC
4 synthase, COX-1, and COX-2. In a rat model of ionophore-induced peritoneal eicosanoid production, SC-57461A inhibits LTB
4 biosynthesis without affecting LTC
4 or 6-keto prostaglandin F
1α production . Oral or topical pretreatment with SC-57461A before challenge with arachidonic acid blocks ear edema in mice.
Biological Activity
Potent and selective inhibitor of LTA 4 hydrolase. Does not inhibit other enzymes of the arachidonic acid cascade including COX-1, COX-2, LTC 4 synthase and 5-lipoxygenase. Potently inhibits LTB 4 production in whole blood (IC 50 = 49 nM). Orally active.