What is the precursor molecule of thrombin?

The precursor molecule of thrombin is prothrombin. Prothrombin is a vitamin K-dependent plasma protein produced by the liver, and it plays a crucial role in the coagulation cascade. When the coagulation process is activated, prothrombin is converted into thrombin through the action of factor X (activated) in conjunction with factor V.

Thrombin then acts to cleave fibrinogen into fibrin, aiding in the formation of a stable blood clot. Understanding this conversion is essential, as thrombin is a key enzyme in hemostasis and coagulation. This highlights the importance of prothrombin as the direct precursor of thrombin.