Enterokinase is a heterodimeric serine protease produced by cells in the duodenal wall. It converts trypsinogen to trypsin, indirectly activating a number of pancreatic digestive enzymes. Enterokinase is a key enzyme for intestinal digestion of proteins and its deficiency may cause severe protein malabsorption. Enterokinase also plays an important role in acute experimental and clinical pancreatitis. The high degree of specificity exhibited by enterokinase for cleaving affinity or other tags from recombinant proteins makes it an ideal tool for use in biochemical applications. The SensoLyte® Rh110 Enterokinase Assay Kit is optimized for detection of enterokinase activity using a fluorogenic substrate. Upon enzyme cleavage, this substrate generates the Rh110 (rhodamine 110) fluorophore with bright green fluorescence that can be detected at excitation/emission=490/520 nm. The longer-wavelength spectra and higher extinction coefficient of the Rh110 provide greater sensitivity and less interference from other reaction components. The assay can detect as low as 0.31 ng/mL active enterokinase.