Thrombin

Definition

Thrombin is an enzyme that plays a crucial role in the blood coagulation process by converting fibrinogen into fibrin, leading to clot formation. It is a key target for various anticoagulant drugs used to prevent and treat thrombotic disorders.

5 Must Know Facts For Your Next Test

1. Thrombin is generated from its inactive precursor, prothrombin, through the action of the enzyme complex prothrombinase.
2. It not only converts fibrinogen to fibrin but also activates factors V, VIII, and XI, amplifying the coagulation cascade.
3. Direct thrombin inhibitors (DTIs) are a class of anticoagulant drugs that specifically target thrombin to prevent clot formation.
4. Heparin enhances the activity of antithrombin III, which inhibits thrombin and other clotting factors.
5. Excessive thrombin activity can lead to pathological conditions like thrombosis, while insufficient activity can result in bleeding disorders.

Review Questions

• What is the primary function of thrombin in the coagulation process?
• How do direct thrombin inhibitors work to prevent clot formation?
• What role does antithrombin III play in regulating thrombin activity?

Related terms

Prothrombin: An inactive precursor of thrombin that is converted by prothrombinase during the coagulation cascade.

Fibrinogen:

A soluble plasma protein that is converted into insoluble fibrin by thrombin during blood clot formation.

Antithrombin III:

A protein that inhibits several enzymes of the coagulation system, including thrombin.