Plastic model of the urokinase molecule

Mature urokinase consists of two polypeptide chains bound together with disulphide bonds. The protein consists of 3 different domains, a protease domain on one chain, and a kringle and EGF-like domain on the other chain. The kringle and EGF-like domains are needed for the interaction of the protein with blood-clotting factors and the release of the protein from the cell, respectively [3][4]. Interestingly, the expression level of urokinase appears to correlate with the process of tumor expansion [5]. The high activity of the urokinase enzyme is considered to lead to degradation of the extracellular matrix and the formation of metastases [6], which suggests that urokinase could be a potential target for cancer therapy [7].