Serine protease inhibitor that inhibits plasmin (90%) (Ki=0.19 nM), trypsin (70%), FXIa/F11 (37%) (Ki=6 nM) and FXa/F10 (20%), and prolonges the activated partial thromboplastin time. This antifibrinolytic property has been confirmed by a fibrin plate assay. Shows less antifibrinolytic activity that aprotinin. In vivo, reduces the bleeding time in a murine bleeding model, and prevents the increase of fibrin(ogen) degradation products in coagulation-stimulated mice. Expressed by the venom gland. Does not inhibit activated protein C (APC), in absence or presence of heparin. This is due to the absence of heparin-binding motifs. Consequently, heparin is unable to enhance the inhibition of activated protein C (APC) by this protein, as it does for DrKIn-I (PubMed:22416129). Does not inhibit tissue plasminogen activator (tPA/PLAT) and urokinase-type plasminogen activator (uPA/PLAU). Does not prolong the prothrombin time (PubMed:23999090). Belongs to the venom Kunitz-type family.