Fibrinolytic system of guinea pig serum

¹ Laboratory for Clinical Biochemistry, Institute of Hematology, Warsaw, Poland and the Medical Research Laboratories, Charing Cross Hospital, London, England

Comparative studies on 10 mammals showed that, in contrast to all the others, guinea pig serum alone, on precipitation with acetic acid, pH 5.3–5.4 at 4°C, yielded a euglobulin with high spontaneous fibrinolytic activity. Fibrinolytic and proteolytic activities of guinea pig, bovine and human euglobulins after addition of streptokinase (SK), SK-human plasminogen mixture, and without any activators were compared; antiplasmin activity was also investigated. When guinea pig serum was substituted for human serum in a mixture of the latter with SK, there was no activation of bovine plasminogen. A plasmin-antiplasmin complex may be the chief component of the guinea pig serum fibrinolytic system.