A portin of amino acids 604-748 from the human protein was used as the immunogen for the Alpha-2-M antibody.
A2-Macroglobulin acts as an antiprotease and is able to inactivate an enormous variety of proteinases. It functions as an inhibitor of fibrinolysis by inhibiting plasmin and kallikrein. It functions as an inhibitor of coagulation by inhibiting thrombin.