Fetuin, Human (Fetuin A, AHSG, Alpha 2-HS Glycoprotein)

The product of the AHSG gene is commonly referred to as fetuin in species other than the human. The first fetal plasma protein to be described was fetuin, which was purified from fetal and newborn calf serum by Pedersen in 1944. Fetuin was subsequently shown to be a very abundant plasma protein in fetal cattle, sheep, pig, and goat, and also to be present in humans and rodents. Fetuins are proteins, which are made in the liver and secreted into the blood. They belong to a large group of binding proteins mediating the transport and availability of a wide variety of substances (drugs, hormones, fatty acids, vitamins etc) in the blood. The best known representative of these carrier proteins is serum albumin, the most abundant protein in the blood plasma of adult animals. Fetuin is more abundant in fetal blood, hence the name fetuin (from lat. fetus). Fetal calf serum contains more fetuin than albumin, while adult serum contains more albumin than fetuin.||Human fetuin is synonymous with 2-HS-Glycoprotein (genetic symbol AHSG),
a2-HS, A2HS, AHS, HSGA and fetuin-A. Fetuin-A exists as a single copy gene in the human and mouse genomes. A closely related gene, fetuin-B also exists in the human, rat and mouse genomes. Like fetuin-A fetuin-B is made predominantly by the liver and to a lesser extent by a number of secretory tissues. Fetuins exist it in all vertebrate genomes including fish and reptiles. Thus fetuins belong to the cystatin superfamily of proteins. Fetuin relatives within this superfamiliy are the histidine- rich glycoprotein (HRG) and kininogen (KNG). Fetuin-A deficiency dramatically increased the calcification proneness of these mice in that all mice sponteneously calcified throughout their body even without mineral-rich diet or surgical tissue trauma. Therefore Fetuin A is regarded as a potent inhibitor of systemic calcification. Fetuins have been implicated in several diverse functions, including osteogenesis and bone resorption, regulation of the insulin and hepatocyte growth factor receptors, and response to systemic inflammation.||Fetuin is a mixture of proteins containing a wider range of growth factors and attachments factors normally found in fetal calf serum. The major protein in fetuin is ~48.5Kd (74% protein; glycosylated). The other minor components of fetuins are alpha-1 and alpha-2 globulins and variety of growth factors such as IGF- 1/2 and FGFs. Fetuins, along with Transferrin, selenium and insulin, have been used in serum-free defined media formulations to increase cell attachment and growth. Fetuin is also an effective serine protease and it may improve cellular viability by inhibiting several proteases.||Source:|Fetuin, from human sera||Molecular Weight:|~49kD||Storage and Stability:|Lyophilized powder may be stored at -20°C. Reconstitute with sterile sterile saline or culture medium. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 6 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.