Enoxaparin is a low molecular weight heparin . It is an anticoagulant used to prevent and treat deep vein thrombosis or pulmonary embolism, and is given as a subcutaneous injection (by a health care provider or the patient). Its use is evolving in acute coronary syndromes (ACS). Enoxaparin binds to and accelerates the activity of antithrombin III. By activating antithrombin III, enoxaparin preferentially potentiates the inhibition of coagulation factors Xa and IIa. The anticoagulant effect of enoxaparin can be directly correlated to its ability to inhibit factor Xa. Factor Xa catalyzes the conversion of prothrombin to thrombin, so enoxaparin's inhibition of this process results in decreased thrombin and ultimately the prevention of fibrin clot formation. Enoxaparin binds to Factor Xa. It does not bind ATIII as the signal peptide is not long enough to bind to ATIII or thrombin.