Heparin bound to antithrombin, molecular model - Stock-Grafiken

Molecular model of heparin (yellow) binding to and activating antithrombin (blue). Heparin is a polysaccharide (sugar) molecule found naturally in the human body that acts as an anticoagulant (prevents the formation of blood clots). Antithrombin is an inhibitor of coagulation proteases, such as thrombin, that promote the formation of blood clots. Therefore activation of antithrombin has an anticoagulant effect.