SC-39026, a specific human neutrophil elastase inhibitor

SC-39026, (+/-) 2-chloro-4-(1-hydroxyoctadecyl)benzoic acid, inhibits human neutrophil Elastase with an IC50 of 0.5 microM (KI of 1.5 microM). Its inhibition of Elastase is reversible and noncompetitive at low concentrations (0.5-1.25 microM). Inhibition is "mixed" at higher inhibitor concentrations. SC-39026 is inactive against hog pancreatic Elastase, bovine alpha-chymotrypsin and Pseudomonas aeruginosa Elastase, but does inhibit human neutrophil Cathepsin G with an IC50 of approximately 2.5 microM. Neutrophil elastases isolated from rat, hamster, rabbit and hog are also inhibited by SC-39026.