Summary
Degradation of 125I-labelled fibrin monomers and 125I-fibrinogen in streptokinase-activated plasma was investigated. Release of the label proceeded at a much higher rate from soluble fibrin monomer complexes than from fibrinogen until ca. 70% of the label was recovered in the serum. It is concluded that the fibrinolytic system has an essentially higher affinity to monomers than to fibrinogen, but that the specificity of the monomers as substrate may be limited to the early steps of degradation. It is suggested that the preferential splitting of fibrin monomer complexes may be important in the body’s defence against pathological fibrin formations derived from paracoagulable fibrin.