Plasminogen is a secreted blood zymogen that is activated by proteolysis and converted to plasmin and angiostatin. Plasminogen plays an important role in fibrinolysis as well as wound healing,cell migration,tissue modeling and angiogenesis. Plasminogen is synthesized in the liver,and it circulates in the blood,with a half-life of 2.2 days. Plasminogen is the precursor of plasmin,which lyses fibrin clots to fibrin degradation products (FDP) and D-dimer; the conversion to active protease is mediated by tissue-type (tPA) and urokinase-type (uPA) plasminogen activators. Defects in plasminogen are likely a cause of thrombophilia and ligneous conjunctivitis.