Fetuin A/AHSG is a human plasma glycoprotein belonging to the Cystatin family of proteases inhibitors. It is highly expressed in embryonic cells and adult hepatocytes, and is expressed to a lesser extent in monocytes/macrophages. Fetuin A/AHSG is a major serum protein component that exerts various calcium dependent physiological activities, and can mediate growth signaling in certain tumor cells. It also can act as a natural antagonist against specific TGF-β and BMP signaling proteins, Recombinant human Fetuin-A is a heterodimeric protein containing a 282 amino acid A chain and a 27 amino acid B chain. Due to glycosylation, recombinant Fetuin-A migrates at an apparent molecular weight of 45 - 55 kDa by SDS-PAGE run under non-reducing conditions.