Fibrinogen (Factor I) and Thrombin (Factor IIa) in the fibrin polymerization pathway (Fibrinogen (Fbg), Thrombin (FIIa))

Fibrin polymerization is a critical process in hemostasis where **thrombin**, a serine protease generated during the coagulation cascade, cleaves specific peptides (FpA and FpB) from **fibrinogen**, a plasma glycoprotein[1][2][3][4][5]. This cleavage produces fibrin monomers, which spontaneously polymerize through a series of knob-hole interactions and protofibril formation, ultimately creating a **fibrin matrix**—the structural backbone of blood clots and wound healing scaffolds[1][2][3][4]. Exogenous administration of thrombin or fibrinogen in medical products accelerates this process to control bleeding or aid tissue regeneration. Altered polymerization dynamics play central roles in a variety of disease states, and modulation of this pathway is a key pharmacological strategy in surgical hemostasis, trauma care, and thrombotic risk management[6][7].

Other names

Fibrinogen (Coagulation Factor I)Thrombin (Coagulation Factor IIa)the fibrin matrixclotting cascade proteins

Thrombin cleaves fibrinogen to form fibrin monomers, which polymerize to build a fibrin network. Exogenous administration bypasses upstream coagulation steps for rapid clot formation. Some drugs inhibit polymerization (anticoagulants), while others supplement via replacement or matrix formation.