Human alpha 1B-Glycoprotein Antibody

A1BG (alpha-1 B/beta-glycoprotein; also C44 [in rodent]) is a 68-80 kDa monomeric plasma glycoprotein member of the Immunoglobulin superfamily of molecules. It is expressed by multiple cell types, principally hepatocytes in response to circulating growth hormone. Initially thought to act as an MMP inhibitor, A1BG is now known to bind to CRISP3, a distant member of a family of venomous molecules. CRISP3 is widely expressed and possesses no toxic properties. But it may play a key role in fertilization, where it temporarily blocks the reaction of PMNs to sperm in the uterus, thus increasing sperm lifespan and the likelihood of fertilization. Within this context, A1BG may regulate CRISP3 availability. A1BG has also been investigated as a biomarker in various cancers. Mature human A1BG is 474 amino acids (aa) in length (aa 22-495) and contains five V-type Ig-like domains. There is one isoform variant that utilizes Met123 as an alternative start site. Full-length human A1BG (aa 22-495) shares only 44% aa sequence identity with mouse A1BG.