Fibrinogen (Fg) is a 340-kd symmetrical heterodimeric protein consisting of three pairs of nonidentical polypeptide chains, and has an overall structure of (A␣/B␤/␥) 2 . This protein is the precursor of fibrin, formed during the hemostatic response. Three separate genes, FGA, FGB, and FGG, located on a 50-kb region of chromosome 4q28-q31, are translated in a coordinated fashion to code for the A␣-, B␤-, and ␥-chains, respectively, of Fg. 1 For its conversion into fibrin, thrombin first catalyzes release of fibrinopeptides A and B from the A␣ and B␤ chains, thus leading to exposure of polymerization sites that organize the initially formed fibrin monomers into a polymeric network of fibers that form the major protein component of the blood clot. This clot is ultimately covalently stabilized by crosslinking of specific ⑀-NH 2 groups of Lys and ␥-COOH groups of Glu residues of fibrin monomer, a process catalyzed by a transglutaminase, namely, activated Factor XIII (FXIIIa). 2

No abstract

No abstract