Urokinase - type plasminogen activator is a serine protease that plays a crucial role in the fibrinolytic system. It is mainly produced and secreted by various cells, such as endothelial cells and monocytes. u - PA specifically converts plasminogen into plasmin, which is capable of degrading fibrin clots and extracellular matrix proteins. This process is essential for maintaining the balance of blood coagulation and fibrinolysis, as well as for tissue remodeling and wound healing. Dysregulation of u - PA has been implicated in many pathological conditions, including thrombosis, cancer metastasis, and inflammatory diseases. Therefore, u - PA is an important target for the development of drugs to treat these diseases.