alpha-Fibrinogenase from Agkistrodon rhodostoma (Malayan pit viper) snake venom

By means of DEAE-Sephadex A-50 column chromatography, Agkistrodon rhodostoma (Malayan pit viper) snake venom was separated into eleven fractions. Fraction II had fibrinogenolytic activity, and when further purified by gel filtration was homogeneous, as judged by sodium dodecylsulfate polyacrylamide gel electrophoresis. It had a single peptide chain with a molecular weight of 25,360 and an isoelectric point greater than 10. The fibrinogenolytic activity was completely destroyed after heating for 30 min at 60 degrees C at pH 5.6, 7.4 or 8.8. This enzyme cleaved specifically the alpha(A) chain of monomeric fibrinogen, without cleaving the beta(B) chain or gamma chain. The specific fibrinogenolytic activity was 51 mg fibrinogen/min per mg protein. This enzyme showed proteolytic activities toward fibrinogen, fibrin and casein, but was devoid of phospholipase A and tosyl-L-arginine methylester esterase activities which are found in the crude venom. The fibrinogenolytic activity was inhibited by EDTA and cysteine, but not by epsilon-aminocaproic acid.