FK-448 Free base slightly inhibits esterolysis of Trypsin and Thrombin, with IC50s of 780 and 35 μM, respectively, but shows no effects on esterolysis of plasmin, plasma kallikrein or pancreas kallikrein, with IC50s of all >1 mM. FK-448 moderately inhibits hydrolytic activities of cathepsin G with an IC50 of 15 μM. FK-448 Free base is an effective and specific inhibitor of chymotrypsin, with an IC50 of 720 nM.

FK-448 (20 mg/kg, p.o.) also decreases the blood glucose level, and increases plasma IRI level in dogs.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.