Molecular Forms of Plasmin and Protease Inhibitors in Human Fibrinolytic Post-Mortem Plasma

Human fibrinolytic post-mortem plasma was studied by G 200 gel filtration (GF), and gel electrophoresis (GE). It contained 2 compounds with plasminogen (PG) + plasmin (P) antigenicity, but no PG. One was a complex between P and α2macro-globulin (α2M) with GF partition coefficient (Kd)=0, and with no evidence of dissociation by GF or GE. It had a BAEesterase activity about that of P in normal plasma, as estimated and calculated from the molar catalytic amount of P (0.48 kU/μmol). The other was eluted later (Kd=0.17) but earlier than PG (Kd=0.33) and migrated between α2 and PG by GE. It had no esterase activity. Both were inactive against casein and fibrin. P was not associated with α1antitrypsin and inter-α-inhibitor.