The alpha2-macroglobulin is a very large size protease inhibitor (725 kDa), primarily synthesized by cells of the hepatic parenchyma. It is involved in the inhibition of enzymes involved in the kinin-kallikrein, complement, coagulation and even fibrinolytic systems. In addition to these inhibitor roles, the alpha2-macroglobulin is used as a carrier for many small peptides (such as cytokines or growth factors), and also with divalent cations (particularly zinc).
The serum concentration of alpha2-macroglobulin varies with the age and gender of the individual.
An increase in serum alpha2-macroglobulin can occur following the nephrotic syndrome. High levels are also associated with estrogen stimulation, as in pregnancy or with oral contraceptive use.
A decrease in the alpha2-macroglobulin concentration can occur due to the inflammatory phase in the case of pancreatitis, and can even indicate the presence of prostate carcinoma. The alpha2-macroglobulin level can also be lower in some individuals due to genetic variation.