Verenväljyysproteiinin

Verenväljyysproteiini, also known as antithrombin, is a protein that plays a crucial role in the human body's blood clotting system. It is synthesized primarily in the liver and endothelium. Its main function is to inhibit the activity of various clotting factors, particularly thrombin (factor IIa) and factor Xa. By neutralizing these enzymes, antithrombin prevents the excessive formation of blood clots, a process essential for maintaining normal blood flow and preventing conditions like thrombosis.

The activity of antithrombin is significantly enhanced by heparin, a glycosaminoglycan. Heparin binds to antithrombin, causing a conformational change that increases its inhibitory efficiency by several orders of magnitude. This interaction is the basis for the therapeutic use of heparin in preventing and treating blood clots.

Deficiencies in antithrombin can be inherited or acquired and are associated with an increased risk of venous thromboembolism, including deep vein thrombosis and pulmonary embolism. Conversely, increased levels of antithrombin are less common and generally not associated with significant clinical consequences. The measurement of antithrombin levels is an important diagnostic tool in evaluating patients with clotting disorders.