What enzyme is responsible for breaking down fibrinogen?

The enzyme responsible for breaking down fibrinogen is plasmin. Plasmin is a serine protease that specifically cleaves fibrin and fibrinogen, playing a crucial role in the process of fibrinolysis, which is the breakdown of blood clots.

When a clot forms, fibrinogen is converted into fibrin by the action of thrombin. However, once it is necessary to remove the clot, plasminogen is activated to plasmin, which then degrades the fibrin network, allowing the clot to dissolve. This process is vital for regulating blood flow and maintaining vascular health after injury or surgical procedures.

Thrombin, while essential in the initial conversion of fibrinogen to fibrin, does not break down fibrinogen itself. Factor V is involved in the coagulation cascade but does not directly participate in the breakdown of fibrinogen. Calcium ions are important for various processes in coagulation but are not enzymes and thus do not perform the breakdown of fibrinogen.