Plasminogen is a beta globulin with a molecular weight of 88,000 D. It is present as a single polypeptide chain with 740 amino acids out of 24 disulfides. Plasminogen is synthesized in the liver. It is also produced and stored in eosinophils and bone marrow. Together with the eosinophilic cells it enters the blood circulation.
In plasma, the plasminogen can be detected at a concentration of 0.06-0.25 mg/l or at an activity of 70-120%. The half-life is +/- 0.92 days.
Together with the fibrinogen, the plasminogen forms complexes. In the course of coagulation, large amounts of this proenzyme are trapped within the fibrin. The fibrinogen is converted into its active form, plasmin, by the activators.