Fibrin degradation products are formed from fibrin through the direct enzymatic action of

D
Plasmin is the principal fibrinolytic enzyme involved in fibrinolysis of fibrin and accounts for the formation of fibrin degradation products (also known as fibrin split products). Other biologically active substances listed here do not have fibrinolytic activity, and some of them, like thrombin, have a diametrically opposite effect on the coagulation process, promoting fibrin formation from fibrinogen. Hageman factor is known as factor XII of the coagulation system and is responsible for the activation of the intrinsic pathway of coagulation. Hageman factor also may cause fibrinolysis indirectly, because it promotes conversion of plasminogen into plasmin.