Plasminogen activator (PA) (PA)

Plasminogen activators are serine proteases that play a pivotal role in the fibrinolytic system by converting the inactive zymogen plasminogen into the active enzyme plasmin [1][4]. The two main endogenous types are tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA), which are encoded by the PLAT and PLAU genes, respectively [2][3]. tPA is primarily involved in dissolving intravascular blood clots, as its enzymatic activity is significantly enhanced when bound to fibrin [1]. In contrast, uPA is largely involved in pericellular proteolysis, tissue remodeling, and cell migration through its interaction with the uPAR receptor [3]. Clinically, recombinant forms of tPA, such as alteplase and tenecteplase, are used as thrombolytic agents to treat acute myocardial infarction, ischemic stroke, and pulmonary embolism [1]. These drugs work by rapidly inducing clot lysis to restore blood flow to vital organs [4]. However, their administration is associated with a high risk of major bleeding complications, most notably intracranial hemorrhage, necessitating careful patient selection [1].

Other names

Tissue-type plasminogen activatorUrokinase-type plasminogen activatortPAuPAFibrinolyticsThrombolytic agentsPLATPLAU

Plasminogen activators catalyze the proteolytic cleavage of the Arg561-Val562 bond in plasminogen, transforming it into the active enzyme plasmin [1][4]. Plasmin then breaks down fibrin polymers, the primary structural component of blood clots, into soluble fragments, thereby facilitating the dissolution of thrombi and restoring blood flow [1]. Therapeutic activators like tPA are often fibrin-selective, meaning they preferentially activate plasminogen that is bound to a clot, thereby limiting systemic proteolysis [4].