Tissue plasminogen activator (abbreviated tPA or PLAT) is a protein involved in the breakdown of blood clots. Specifically, it is a serine protease 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 is used in clinical medicine to treat stroke.
The classic role of tPA is in the clotting system. Specifically, tPA catalyzes the conversion of plasminogen into plasmin. It does so by cleaving the single-chained plasminogen into two chains. These two chains are linked by a disulfide bond and the resulting molecule is called plasmin.
Tissue plasminogen activator is a protein encoded by the PLAT gene, which is located on chromosome 8. The primary transcript produced by this gene undergoes alternative splicing, producing three distinct messenger RNAs.
Recently tPA has been used to dissolve thrombi associated with ischemic strokes and brain injury.
In addition, people with frostbite that were treated with tPA had fewer amputations than those that were not.