ISOLATION AND CHARACTERIZATION OF PROCOAGULANT FROM THE VENOM OF VIPERA-ASPIS-ASPIS

1. A procoagulant protein was isolated from Vipera aspis aspis (Aspic viper) venom by Sephadex G-75, DEAE-Sephacel, Q-Sepharose and Sephadex G-150 column chromatography. 2. The purified protein has a molecular weight of 125,000 and an isoelectric point of 4.3. 3. This procoagulan t decreased the clotting time of plasma from humans, however, direct f ibronogen clotting activity was not detected. 4. Diisopropyl fluoropho sphate, a serine-protease inhibitor affected coagulant activity of pur ified protein significantly, while a factor Xa inhibitor (3-ABPE) poss essed a slight inhibitory effect. 5. Bovine prothrombin incubated with isolated protein, phospholipid emulsion, bovine factor V and calcium ions drastically decreased the clotting time of fibrinogen and express ed hydrolytic activity against synthetic arginine esterase substrates. However, no hydrolytic activity these substrates was detected with th e procoagulant alone indicating that this protein might participate in activation of prothrombin.