Urokinase (urokinase-type plasminogen activator or uPA, EC 3.4.21.73) is a serine protease, which catalyzes the conversion of the plasminogen to active plasmin, which in turn participates in thrombolysis. Biovision’s Urokinase Fluorimetric Activity Assay Kit utilizes an AMC-based peptide substrate containing the recognition sequence for Urokinase. Urokinase present in the sample catalyzes the cleavage of the substrate and releases AMC, which can be easily quantified by measuring its fluorescence at Ex/Em = 350/450 nm. This sensitive assay detects very low levels of Urokinase activity in biological samples (as low as 0.02 IU/ml).