Thrombin (human)

Thrombin is the last enzyme in the clotting cascade functioning to cleave fibrinogen to fibrin and potentiates the procoagulation process by activating factors V, VIII, XI, and XIII.{12316} Conversely, thrombin aids the anticoagulant process by activating protein C.{8110} Activated protein C inhibits activated factors V and VIII ultimately down-regulating further thrombin production. Thrombin is often used as a potent platelet activator in vitro. Platelet responses to thrombin are mediated through protease-activated receptors (PARs). {15268} Thrombin-mediated signaling regulates a diverse range of metabolic processes including activation of phospholipases in platelets, endothelial cells, and cardiac myocytes.{6006}