IC50: 720 nM (Chymotrypsin)

FK-448 Free base is an effective and specific inhibitor of chymotrypsin, with an IC ₅₀ of 720 nM. FK-448 Free base slightly inhibits esterolysis of Trypsin and Thrombin, with IC ₅₀ s of 780 and 35 μM, respectively, but shows no effects on esterolysis of plasmin, plasma kallikrein or pancreas kallikrein, with IC ₅₀ s of all >1 mM. FK-448 moderately inhibits hydrolytic activities of cathepsin G with an IC ₅₀ of 15 μM.

FK-448 (20 mg/kg, i.p.) results in a decrease in the blood glucose level, and inhibits the degradation of insulin by pancreatic enzymes in rats. FK-448 (20 mg/kg, p.o.) also decreases the blood glucose level, and increases plasma IRI level in dogs.