21. Unlike antithrombin , hirudin binds to and inhibits only the activated thrombin, with a specific activity on fibrinogen. 22. Idraparinux also binds antithrombin III, however with a 30-fold increase in affinity as compared to Fondaparinux. 23. Other than antibodies to thrombin, antibodies to vascular heparin sulfate appear to interfere with antithrombin -thrombin interaction. 24. The powerful protein was discovered hiding inside antithrombin III, which helps regulate the body's blood clotting system. 25. Unexpectedly the protein crystallized as a heterodimer composed of one molecule of native antithrombin and one molecule of latent antithrombin. 26. Unexpectedly the protein crystallized as a heterodimer composed of one molecule of native antithrombin and one molecule of latent antithrombin . 27. The archetypal example of this situation is antithrombin , which circulates in plasma in a partially inserted relatively inactive state. 28. The heparin pentasaccharide-bound form of antithrombin is, thus, a more effective inhibitor of thrombin and factor Xa. 29. AT III is generally referred to solely as " Antithrombin " and it is Antithrombin III that is discussed in this article. 30. AT III is generally referred to solely as " Antithrombin " and it is Antithrombin III that is discussed in this article.
