Esterase and Clotting Activity Derived From Purified Prothrombin

Abstract

Purified prothrombin can be activated in several ways to obtain biothrombin. This thrombin possesses the properties of activating fibrinogen, catalyzing the activation of prothrombin, neuralizing antithrombin, dissolving fibrin clots and has esterase activity. In 0.05 m calcium solutions prothrombin activates to yield first and later predominantly esterase activity. Prothrombin preparations dried and stored for 5 years and then dissolved in 0.05 m calcium solutions yield almost exclusively esterase activity and very little activity for the clotting of fibrinogen. The esterase activity obtained from prothrombin is not equated with the clotting activity. It is possible to have only esterase activity or esterase with clotting activity. When the material derived from prothrombin possesses only esterase activity it is called esterase thrombin. Esterase thrombin can also be obtained from biothrombin by simply allowing biothrombin solutions to stand at room temperature a few days or by using chemicals such as ninhydrin. Esterase thrombin does not catalyze the conversion of prothrombin to thrombin but does dissolve fibrin clots, and although it interacts with antithrombin the kinetics are not the same as with biothrombin.