α₂-macroglobulin (α₂M)

Abstract

A serum glycoprotein working as inhibitor of a number of proteases including thrombin, plasmin, kallikrein, trypsin, chymotrypsin, elastase, collagenase and cathepsin B and G. α₂M is produced mainly by macrophages and regulates the proteolytic balance in a number of extracellular processes that exert their action mainly in blood coagulation, fibrinolysis and inflammation. α₂M and protease complexes are proteolytically inactive and are eliminated quickly (in minutes) from the circulation. Its serum levels are increased especially in nephrotic syndrome, atopic dermatitis, diabetes mellitus and ataxia-telangiectasia.