Alpha 2-antiplasmin

Alpha 2-antiplasmin (also known as α2-antiplasmin or plasmin inhibitor) is a type of serine protease inhibitor (serpin) that plays a crucial role in the regulation of blood coagulation and fibrinolysis. It is produced in the liver and circulates in the bloodstream, where it inhibits the activity of plasmin, a proteolytic enzyme that breaks down fibrin, a protein involved in blood clotting.

Structure and Function

Alpha 2-antiplasmin is a single-chain glycoprotein with a molecular weight of approximately 70,000 daltons. It is composed of 464 amino acids and has a complex tertiary structure that includes several alpha helices and beta sheets.

The primary function of alpha 2-antiplasmin is to inhibit the activity of plasmin, thereby preventing the breakdown of fibrin and helping to maintain the integrity of blood clots. It does this by binding to free plasmin molecules and forming a stable, inactive complex. This inhibitory activity is crucial for the regulation of fibrinolysis and the prevention of excessive bleeding.

Clinical Significance

Deficiency in alpha 2-antiplasmin can lead to a bleeding disorder known as alpha 2-antiplasmin deficiency, which is characterized by prolonged bleeding times and a tendency to bruise easily. This condition is rare and is usually inherited in an autosomal recessive manner.

Conversely, elevated levels of alpha 2-antiplasmin can lead to a hypercoagulable state, increasing the risk of thrombosis and embolism. This can occur in certain pathological conditions, such as liver disease, cancer, and sepsis.

Alpha 2-antiplasmin is also a potential therapeutic target in the treatment of thrombotic disorders, such as deep vein thrombosis and pulmonary embolism. Inhibitors of alpha 2-antiplasmin could potentially be used to enhance fibrinolysis and prevent the formation of pathological blood clots.

See Also

• Coagulation
• Fibrinolysis
• Plasmin
• Serine protease inhibitor