t-Plasminogen Activator/tPA: Proteins and Enzymes

tPA (tissue-type Plasminogen Activator) is a serine protease that is secreted by vascular endothelial cells, fibroblasts, neurons, microglia, and astrocytes. The partially active single chain can be further processed to full activity by Plasmin, Kallikrein 1, or Coagulation Factor Xa.  Active tPA converts Plasminogen to Plasmin, a fibrinolytic protease, by hydrolyzing an Arg-Val peptide bond in Plasminogen. Unusually high levels of tPA activity can result in excessive bleeding, and ...