Hirudin (54-65) (sulfated)

[Tyr(SO3H)63]-hirudin fragment 54-65 has been used to study the effect of thrombin in presence of leupeptin. It is also used to study the effect of hirudin peptide on the thrombin-rHCII (recombinant heparin cofactor II)-L444R (leucine 444 to arginine) complex separation.

Hirudin fragment th at binds to the regulatory exosite I on thrombin and the regulatory proexosite I on prothrombin. The interaction with thrombin prevents the thrombin-induced activation of clotting factor V. The interaction with prothrombin inhibits the formation of thrombin by factor Xa in the presence of factor Va.