Purification and biochemical characterization of FIIa, a fibrinolytic enzyme from Agkistrodon acutus venom

A fibrinolytic enzyme, F IIa, was isolated from Agkistrodon acutus venom by ion-exchange chromatography and gel filtration. F IIa consisted of a single polypeptide chain with a molecular weight of 26,000 and an isoelectric point of 4.6. F IIa was shown to solubilize fibrin and fibrinogen. F IIa cleaved, primarily, the a chain of fibrinogen and fibrin followed by the P chain. while the gamma chain was minimally affected. Thus, the enzyme was an alpha,beta -fibrinogenase. The cleavage pattern of fibrinogen clearly varied from plasmin cleavage of the same molecule. In vivo, F IIa had no influence on the rat's tissue-type plasminogen activator and plasminogen activator inhibitor-1 activities in plasma. At the dosage of 5 mg/kg, histological examination of heart, liver and lung tissue showed no hemorrhage. F IIa is an enzyme that hydrolyzed fibrin directly without hemorrhagic activity. (C) 2001 Elsevier Science Ltd. All rights reserved.