Poly P activates the kallikrein-kinin system and coagulation and inhibits fibrinolysis. Upon platelet activation, poly P is released from the dense granules to activate factor XII (FXII), which in turn activates prekallikrein (PK), consequently increasing bradykinin (BK) levels. Activated FXII also activates factor XI (FXI). By binding to thrombin (FII), poly P enhances thrombin-mediated factor V (FV) activation, promoting coagulation. In addition, Poly inhibits fibrinolysis by increasing TAFI activity and binding to fibrin (Fb) clots, making them more resistant to lysis.