[Fast-acting plasminogen activator inhibitor in the plasma]

This study contains a survey of papers published in the last few years on the specific inhibitor of plasminogen activation (PA-inhibitor, or antiactivator) discovered in plasma in 1983. Molecular weight of the PA-inhibitor is ranging from 40,000 to 50,000; the antiactivator is present in very small concentration in plasma. Most probably it originates from the endothelial cells. The antiactivator inhibits both tissue plasminogen activator and urokinase, forming complexes in molar ratio 1:1 with them. Possibly, it is the main plasmic inhibitor of plasminogen activators. Its increased content in plasma of patients with tendency to develop thromboembolic disease points to a relationship between lowered fibrinolytic activity and increased concentration of the PA-inhibitor in blood.