Fibrinogen

Literature References: A plasma glycoprotein belonging structurally to the keratin-myosin group. Synthesized and secreted by hepatic parenchymal cells. Present to the extent of 0.3-0.4 g/100 ml in human plasma. Essential to the clotting of blood. Its synthesis is greatly increased during acute inflammatory challenge. The fibrinogen molecule consists of three peptide chains, a (A), b (B), and g (C), crosslinked by several disulfide bonds. The mol wt of about 400,000 represents a dimeric form of the molecule. Thrombin releases fibrinopeptides A and B from the N-terminal ends of the a and b chains of fibrinogen in the formation of fibrin during coagulation. Because fibrinogen is less sol than other plasma proteins it is readily separated by precipitation with sodium chloride: Florkin, J. Biol. Chem. 87, 629 (1930); or with ammonium sulfate: Nanninga, Arch. Neerl. Physiol. 28, 241 (1946). Prepn from human plasma: Edsall et al., J. Am. Chem. Soc. 69, 2731 (1947). Purification: Cama et al., Naturwissenschaften 48, 574 (1961). End group determination: Lorand, Middlebrook, Science 118, 515 (1953). Structure studies: Schauenstein, Hochenegger, Z. Naturforsch. 8b, 473 (1953); Edsall, J. Polym. Sci. 12, 253 (1954). Reviews: Seegers, Physiol. Rev. 34, 711 (1954); Lorand, Fed. Proc. 24, no. 4, part 1, 784 (1965); several authors, Thromb. Diath. Haemorrh. Suppl. 39 (1970); A. L. Copley, Thromb. Res. 14, 249 (1979). Fibrinogen has been shown to be the receptor for the endogenous lectin (agglutinin) secreted by activated platelets: T. K. Gartner et al., Nature 289, 688 (1981). Review of biosynthesis: G. M. Fuller, D. G. Ritchie, Ann. N.Y. Acad. Sci. 389, 308-322 (1982).