|Detection of Human Fibrinogen by Western Blot. Western blot shows purified human fibrinogen. PVDF membrane was probed with 0.1 µg/mL of Sheep Anti-Human Fibrinogen Antigen Affinity-purified Polyclonal Antibody (Catalog # AF4786) followed by HRP-conjugated Anti-Sheep IgG Secondary Antibody (Catalog # HAF016). Specific bands were detected for Fibrinogen at approximately 70-80 kDa (as indicated). This experiment was conducted under reducing conditions and using Immunoblot Buffer Group 8.|
Fibrinogen is a 340 kDa, secreted glycoprotein complex that is found in blood at concentrations of 150-400 mg/dL. It is secreted primarily by hepatocytes, but is also reported to be expressed by fibroblasts, type I alveolar epithelium, intestinal epithelium and some tumor cells. Fibrinogen is a homodimer that is composed of two, three-polypeptide chain subunits. In human, each subunit contains one 847amino acid (aa) alpha chain, one 461 aa beta chain, and one 427 aa gamma chain. Multiple interchain disulfide bonds link all three polypeptides. Fibrinogen plays a central role in clot formation. Conversion of fibrinogen to fibrin is triggered by thrombin, which cleaves fibrinopeptides A and B from alpha and beta chains, and thus exposes the N-terminal polymerization sites responsible for the formation of the soft clot. The soft clot is converted into the hard clot by factor XIIIA which catalyzes the epsilon-(gamma-glutamyl)lysine cross-linking between gamma chains (stronger) and between alpha chains (weaker) of different monomers. Fibrinogen is also a component of the ECM and binds to cell surface molecules on inflammatory cells. Mature human alpha, beta and gamma -chains share 67%, 85% and 83% aa identity with mouse alpha, beta and gamma -chains, respectively.