Fibrinogen

Fibrinogen is a coagulation factor, precursor of fibrin. It is a plasmatic protein that is formed in the liver. Physiological concentration of fibrinogen in plasma is 3–5 g/l. Fibrinogen is also present in α-granules of blood plateles.

Fibrinogen is a symmetrical dimer composed of three pairs of polypeptide non-identical chains, that are bound by disulfide bonds. During hemocoagulation fibrinopeptide A is cleaved by the action of the proteolytic enzyme trombin and fibrin monomer is formed. Then thrombin cleaves fibrinopeptide B and fibrin monomers are polymerized.

During plasma electrophoresis, it ranges between β- and γ-globulins.

Fibrinogen is an acuse phase protein. Plasmatic concentration of fibrinogen rises during the acute response of the organism. Fibrinogen is a risk factor of atherosclerosis. Plasmatic concentration may decrease because of insufficient production (in severe hepatopathies) or increased consumption (DIC).