Tissue plasminogen activator
![](/Images/godic/202412/20/Protein_PLAT_PDB_1a5h3404.png")
![](/Images/godic/202412/20/PBB_GE_PLAT_201860_s_at_tn3405.png")
![Here is tPA in its full structure. In magenta is the Protease domain. In blue, is Kringle 1. Yellow highlights Kringle 2. Green marks Epidermal Growth Factor. Red shows the Finger domain. Glycosylation occurs at N117, N184, and N448](/Images/godic/202412/20/T-PA3405.gif")
![A simplified illustration demonstrates clot breakdown (fibrinolysis), with blue arrows denoting stimulation, and red arrows inhibition.](/Images/godic/202412/20/Fibrinolysis3405.png")
Tissue plasminogen activator (abbreviated tPA or PLAT) is a protein involved in the breakdown of blood clots. It is a serine protease (EC3.4.21.68) found on endothelial cells, the cells that line the blood vessels. As an enzyme, it catalyzes the conversion of plasminogen to plasmin, the major enzyme responsible for clot breakdown. Because it works on the clotting system, tPA (such as alteplase, reteplase, and tenecteplase) is used in clinical medicine to treat embolic or thrombotic stroke. Use is contraindicated in hemorrhagic stroke and head trauma. The antidote for tPA in case of toxicity is aminocaproic acid.