Serine protease inhibitor; inhibits trypsin, plasmin, plasma kallikrein and thrombin (IC50 values are 9.4, 30, 41 and 110 μM respectively). Antithrombotic in vitro and in vivo. Also inhibits LPS-induced TNF-α production, probably by inhibiting NF-κB and AP-1 activation. Purity 98%. MW (observed): 417.48