It is the activated form of prothrombin, a circulating zymogen. Thrombin cleaves fibrinogen to fibrin, which in turn participates directly in the formation of a blood clot. In addition to its use as a reagent for coagulation studies, thrombin has been exploited as a tool for specific cleavage of recombinant fusion proteins.
Bovine thrombin is known to cleave after arginine residues.
Specific sequences are given in Suggestions For Use. Prothrombin is a single polypeptide of molecular weight approximately 70,000 daltons. Optimized conditions for thrombin with a synthetic substrate are shown below. Enzyme may not be stored diluted. Pipette 0.867 ml buffer into a cuvette.