Analysis Note

The NIH assay procedure uses 0.2 ml diluted plasma (1:1 with saline) as a substrate and 0.1ml 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.

Application

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 that compared efficacy and safety of low-molecular-weight heparins (LMWHs) to other anticoagulants as venous thromboembolism prophylaxis in major orthopedic surgery.

Biochem/physiol Actions

Serine protease that selectively cleaves Arg-Gly bonds in fibrinogen to form fibrin and fibrinopeptides A and B.

General description

Thrombin is the final coagulation protease in regard to hemostasis, promoting both procoagulant and anticoagulant effects.

Other Notes

View more information on thrombin at www.sigma-aldrich.com/enzymeexplorer.

Reconstitution

When reconstituted with 1 ml H₂O, one vial will contain 10 mg bovine serum albumin, 0.15 M NaCl and 0.05 M sodium citrate, pH 6.5

Unit Definition

Activity is expressed in NIH units obtained by direct comparison to a NIH Thrombin Reference Standard