Antithrombin III from human plasma

SerpinC1, also known as antithrombin III (AT III), is a member of the serpin superfamily of serine protease inhibitors. The gene is mapped to human chromosome 1. SerpinC1 is a glycoprotein with three β-sheets and nine α-helices. The protein has an active site region and a heparin binding site.

SerpinC1, also known as antithrombin III (AT III), has been found to be a marker for disseminated intravascular coagulation (DIC) and to be of prognostic significance in septic patients. Antithrombin III synthesized in the liver is the principal plasma serpin of blood coagulation proteases and inhibits thrombin and other factors such as Xa by the formation of covalently linked complexes. Thus, it is one of the most important coagulation inhibitors and the fundamental enzyme for the therapeutical action of heparin. The inhibitory activity of AT III undergoes a dramatic increase in the presence of heparin and other glycosaminoglycans. Antithrombin III mediates the promotion of prostaglandin release, an inhibitor of leucocyte activation and downregulation of many proinflammatory cytokines. It exerts anti-inflammatory properties in addition to its anti-coagulative mechanisms. The deficiency or functional abnormality of AT III may result in an increased risk of thromboembolic disease, such as deep vein thrombosis and pulmonary embolism. In addition, it has been reported that AT III can alter or influence inflammatory processes via inhibition of NF (nuclear factor)-κB activation or actin polymerization. It is found in normal serum at 15mg/100mL. Found at higher levels in plasma than in serum because of complexing with thrombin during coagulation. Clinically, reduced levels are indicative of hypercoagulability. Reduction in the levels of antithrombin III enhances the severity of renal ischemia/reperfusion injury.

Lyophilized from 50 mM Tris-HCl, pH 8.0, with 150 mM NaCl.

In water or aqueous buffer