Plasminogeeni

Plasminogen is a serine protease zymogen produced by the liver and is found in the blood plasma of humans and other mammals. It plays a crucial role in the fibrinolytic system, which is responsible for dissolving blood clots. Plasminogen is converted into its active form, plasmin, by tissue plasminogen activator (tPA) or urokinase-type plasminogen activator (uPA) in the presence of fibrin. Plasmin then degrades fibrin, thereby dissolving the clot.

Plasminogen is a single-chain glycoprotein consisting of 724 amino acids. It has a molecular weight of approximately 92 kDa and is synthesized as a precursor protein that undergoes post-translational modifications, including glycosylation and cleavage to form the active plasminogen molecule. The primary structure of plasminogen includes a kringle domain, which is involved in binding to fibrin, and a plasmin domain, which is responsible for the catalytic activity of plasmin.

Plasminogen levels in the blood are tightly regulated and can be influenced by various factors, including age, sex, and certain medical conditions. Low levels of plasminogen are associated with an increased risk of thrombosis, while high levels may indicate an increased risk of bleeding. Plasminogen can also be used as a diagnostic marker for certain diseases, such as liver disease and cancer.

In summary, plasminogen is a vital component of the fibrinolytic system, responsible for the dissolution of blood clots. Its levels in the blood are regulated and can be influenced by various factors, making it an important biomarker for certain medical conditions.