A purified procoagulant enzyme from the venom of the eastern diamondback rattlesnake (Crotalus adamanteus): in vivo and in vitro studies.

Abstract A procoagulant enzyme in the venom of the eastern diamondback rattlesnake, Crotalus adamanteus , has been isolated and purified. The enzyme acts directly on purified fibrinogen or fibrinogen in plasma, forming a friable fibrin clot. The enzyme does not activate factors of the extrinsic system, nor does it activate factor XIII. It also does not aggregate platelets and is not inhibited by heparin. Incubation with plasma produces insignificant changes in all coagulation factors except fibrinogen. The enzyme does not activate components of the fibrinolytic system, but is itself fibrinolytic at extremely high concentration. Infusion into dogs produces well tolerated hypofibrinogenemia lasting up to 8 hours. Post infusion, intense fibrinolysis is observed with high titers of nonclottable fibrinogen derivatives in the serum, some with an electrophoretic mobility similar to native fibrinogen. Following infusion declines in factors II, V, and VIII were noted by one stage assays, but may be artifactual due to high levels of fibrinogen derivatives in the test plasmas.