Characterisation and some properties of the protein C activator from Agkistrodon Contortrix Contortrix venom.

The protein C activator (PCA) detectable in the venom of Agkistrodon Contortrix Contortrix (ACCV, Southern Copperhead) by specific immunochromometric assay and anticoagulant activity has been isolated and partially characterized. Chromatography of the crude venom on SP-Sephadex followed by Con A Sepharose and finally on hydroxylapatite was necessary to achieve an electrophoretically - pure product. The isolated PCA is a single chain glycoprotein with strong positive charge and an apparent molecular weight of 36,000. It had an immediate-inhibiting effect on the activated partial thromboplastin time (APTT) of normal plasma with no noticeable effect on the prothrombin time. Its prolonging effect on the APTT was dependent on protein C and it appeared to interfere with the contact mechanism rather than with factors V and VIII. It had enzymatic activity on some tripeptide chromogenic substrates sensitive to thrombin and kallikrein. When mixed with normal plasma it generated activity on substrates sensitive to activated protein C and should be useful for studies of protein C.