Human fetuin (2-Heremans-Schmid-glycoprotein or α2-HS-glycoprotein) is a major plasma glycoprotein predominantly synthesized in the liver. Human fetuin is named after its bovine homolog. Fetuins are found in most mammals. Human fetuin is a negative acute-phase protein; normal circulating levels in adults (300–600 μg/ml) fall significantly (30–50%) during injury and infection. The biological role of fetuin is unknown, although it has been implicated as an immunomodulator that can participate in stimulation of bacterial phagocytosis by neutrophils and promotion of endocytosis by mouse macrophages. Hepatocytes are the principal cell source of circulating fetuin, but it also is expressed by monocyte/macrophages. Fetuins occur in large amounts in blood and cerebrospinal fluid and accumulate to high concentrations in calcified bone. The fetuin promoter region has several potential interleukin 6-responsive elements, and its synthesis is down-regulated during injury and inflammation. Fetuin is an acidic glycoprotein with three N-linked and three O-linked oligosaccharide chains, whose terminal sugar residues are rich in sialic acid (N-acetylneuraminic acid), contributing to its net negative charge. A role for fetuin as a carrier of bioactive molecules has been proposed based on observations that it binds and carries Ca2+ ion. Fetuin is implicated in bone remodeling, immune function and may play a role in tumor progression of certain cell types.
Synonyms: 59 kDa bone sialic acid-containing protein antibody, A2HS antibody, Aa2-066 antibody, AHS antibody, Ahsg alpha-2-HS-glycoprotein antibody, AHSG antibody, Alpha 2 Z globulin antibody, Alpha-2-HS-glycoprotein antibody