protrombinu
Protrombina, also known as prothrombin, is a vitamin K–dependent plasma glycoprotein produced by the liver. It circulates as a zymogen (inactive enzyme) that is activated to thrombin, the central enzyme of the coagulation cascade. In the coagulation process, prothrombin is converted into thrombin by the prothrombinase complex, which includes factor Xa, factor Va, calcium ions, and a phospholipid surface. Thrombin then cleaves fibrinogen to fibrin, promotes platelet activation, and amplifies clot formation by activating factors V, VIII, XI, and XIII.
Structure and genetics: The F2 gene encodes prothrombin. The protein is synthesized as a single chain and
Clinical aspects: Prothrombin levels influence clotting ability. Vitamin K deficiency, liver disease, or anticoagulants such as
Medical uses: Prothrombin complex concentrates, containing factors II, VII, IX, and X, are used for rapid reversal