Description_x000D_ General description_x000D_ Thrombin is the final coagulation protease in regard to hemostasis, promoting both procoagulant and anticoagulant effects._x000D_ Application_x000D_ Thrombin is used for site specific cleavage of recombinant fusion proteins containing an accessible thrombin recognition site for removal of affinity tags. Thrombin has been used in a study to assess global haemostasis and point of care testing._x000D_ Biochem/physiol Actions_x000D_ Serine protease that selectively cleaves Arg-Gly bonds in fibrinogen to form fibrin and fibrinopeptides A and B._x000D_ Unit Definition_x000D_ Activity is expressed in NIH units obtained by direct comparison to a NIH thrombin reference standard._x000D_ Physical form_x000D_ Lyophilized from saline sodium citrate buffer, pH 6.5_x000D_ Analysis Note_x000D_ Activity is expressed in NIH units obtained by direct comparison to a NIH Thrombin Reference Standard, Lot K._x000D_ The NIH assay procedure uses 0.2 mL of diluted plasma (1:1 with saline) as a substrate and 0.1 mL of thrombin sample (stabilized in a 1% buffered albumin solution) based on a modification of the method of Biggs. Only clotting times in the range of 15-25 seconds are used for determining thrombin concentrations._x000D_ Other Notes_x000D_ View more information on thrombin at www.sigma-aldrich.com/enzymeexplorer.