Fibrineihin

Fibrineihin, also known as fibrinogen, is a soluble glycoprotein present in the blood plasma of vertebrates. It plays a crucial role in the coagulation process, which is essential for preventing excessive bleeding following injury. Fibrinogen is synthesized primarily in the liver and constitutes about 4% of the total plasma protein content.

The coagulation cascade involves a series of enzymatic reactions that ultimately convert fibrinogen into fibrin, a fibrous protein that forms a mesh-like structure. This mesh stabilizes blood clots by trapping platelets and blood cells. The conversion of fibrinogen to fibrin is catalyzed by the enzyme thrombin, which cleaves specific peptide bonds in fibrinogen, exposing polymerization sites that allow fibrin monomers to link together.

Fibrinogen is a hexameric molecule composed of two sets of three polypeptide chains: Aα, Bβ, and γ. These chains are held together by disulfide bonds and are arranged in a triangular structure. The molecule contains several functional domains, including the fibrinogen-binding sites for thrombin and the polymerization sites that facilitate clot formation.

Elevated levels of fibrinogen are associated with increased risk of cardiovascular diseases, such as atherosclerosis and thrombosis, due to its role in promoting clot formation. Conversely, deficiencies in fibrinogen can lead to bleeding disorders, such as afibrinogenemia, which may result in prolonged bleeding after injury or surgery. Genetic mutations affecting fibrinogen structure or function can also contribute to these conditions.

Fibrinogen levels can be measured in the laboratory through various assays, including the Clauss method, which quantifies the clotting activity of fibrinogen. Monitoring fibrinogen levels is important in clinical settings, particularly for patients undergoing surgery, managing bleeding disorders, or at risk of thromboembolic events.