Abstract
Fibrolase, a fibrinolytic enzyme isolated from Agkistrodon c. contortrix (southern copperhead) venom, solubilizes fibrin primarily by rapid hydrolysis of the alpha and beta chains. Fibrolase is also an A alpha , B beta fibrinogenase. The breakdown products of fibrin and fibrinogen following incubation with fibrolase were different from those observed with plasmin. This enzyme is a metalloprotease that was inhibited by ethylenediamine-tetraacetic acid. Fibrolase was inhibited by dithiothreitol, suggesting that disulfide bonds are important for catalytic activity. It was also inhibited by alpha sub(2)-macroglobulin, but not by the soybean or lima bean trypsin inhibitors, diisopropyl-fluorophosphate, or p-hydroxymercuribenzoate. Unlike thrombolytic agents such as streptokinase, fibrolase does not activate plasminogen as evidenced by the use of plasmin-specific chromogenic substrate S-2251 and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.