Urokinase or Urokinase-type plasminogen activator (uPA) is a serine protease (EC 3.4.21.73). It is secreted as a single-chain zymogen, pro-Urokinase, possessing little or no intrinsic enzymatic activity. The single chain zymogen is converted into the active two chain enzyme (tcuPA) by cleavage of the bond between Lys158 and Ile159. After activation, Urokinase specifically cleaves the proenzyme plasminogen to form the active enzyme plasmin. The active plasmin then catalyzes the breakdown of fibrin polymers of blood clots. Urokinase is involved in a number of biological functions including fibrinolysis, embryogenesis, cell migration, tissue remodeling, ovulation, and wound healing. Additionally, it is a potent marker of invasion and metastasi