No abstract

A complex between plasmin and an inhibitor was isolated by affinity chromatography from urokinase-activated human plasma. The complex did not react with antibodies against any of the known proteinase inhibitors in plasma. A rabbit antiserum against the complex was produced. It contained antibodies against plasminogen+plasmin and an a2 protein. By crossed immunoelectrophoresis the a2 protein was shown to form a complex with plasmin, when generated by urokinase in plasma, and with purified plasmin. The a2 protein was eluted by Sephadex G-200 gel filtration with KD approx. 0.35, different from the other inhibitors of plasmin in plasma, and corresponding to an apparent relative molecular mass (Mr) of about 75000. By sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, the Mr of the complex was found to be approx. 130000. After reduction of the complex two main bands of protein were observed, with Mr about 72000 and 66000, probably representing an acyl-enzyme complex of plasmin-light chain and inhibitorheavy chain, and a plasmin-heavy chain. A weak band with Mr 9000 was possibly an inhibitor-light chain. The inhibitor was partially purified and used to titrate purified plasmin of known active-site concentration. The inhibitor bound plasmin rapidly and strongly. Assuming an equimolar combining ratio, the concentration of active inhibitor in normal human plasma was estimated to be 1.1 umol/l. A fraction about 0.3 of the antigenic inhibitor protein appeared to be functionally inactive. In plasma, plasmin is primarily bound to the inhibitor. Only after its saturation does lysis of fibrinogen and fibrin occur and a complex between plasmin and a2 macroglobulin appear.

No abstract

The fibrinolytic agent produced by certain stone(2) showed that in addition to the strepstreptococci (streptokinase) was originally tococcal factor, a "lytic factor" in serum was thought to be a iibrinolytic enzyme( 1 ). Mil-necessary for the production of fibrinolysis.Later, Christensen ( 3 ) found that plasmino-* Preliminary Communication: The 2nd Internagen, a precursor in blood, was transformed to