Human alpha1-Microglobulin Antibody

Human alpha1-Microglobulin (alpha1-m/A1M; also protein HC) is a secreted, 31-32 kDa glycoprotein member of the lipocalin family, calycin superfamily of molecules. It is expressed by hepatocytes, keratinocytes, and endodermal derivatives in the embryo. A1M appears to act as a heme scavenger, protecting cells and collagen against oxidative damage. It also acts as an immunosuppressant, inhibiting polyclonal lymphocyte activation and dampening granulocyte migration in response to chemokines. A1M circulates either as a monomer, or bound to IgA, albumin or prothrombin. Human A1M is generated through cleavage of a precursor molecule termed AMBP. This AMBP should not be confused with AMBP-1, a 120-140 kDa adrenomedullin-binding protein that is also known as Complement Factor H. The AMBP precursor contains a 19 aa signal sequence, an N-terminal 183 aa A1M protein (aa 20-203), and a C-terminal serine protease inhibitor termed bikunin (aa 206-352). A1M possesses one lipocalin domain (aa 42-186). Although cleavage of AMBP in the Golgi apparatus typically generates a 31 kDa A1M and 28 kDa bikunin molecule, the 60-65 kDa AMBP precursor can also be released intact. A1M will undergo extracellular processing, generating a 30 kDa isoform that is missing aa 199-203. There is one splice variant that shows a deletion of aa 48-57. Over aa 20-203, human A1M shares 76% aa sequence identity with both mouse and rat A1M.