When Is Plasmin Activated?

Plasminogen must be activated to dissolve fibrin. Tissue plasminogen activator (tPA) is released by endothelial cells in damaged blood vessels. tPA is a serine protease and catalyzes the conversion of plasminogen into plasmin by cleaving the bond between arginine 561 and valine 562 and removing the N-terminal portion.

How does plasmin become activated?

Binding clots or cell surface causes its conformation to change, allowing it to be activated by plasminogen activators. Plasminogen activators do so by cleaving the R561/V562 peptide bond, producing the active protein plasmin, which catalyzes the degradation of fibrin polymers that make up the structure of blood clots.

What does activation of plasmin do?

[1] Regulation of the activation of plasminogen functions to control the homeostasis between fibrin deposition and fibrinolysis particularly in the setting of hemostasis.