SensoLyte Enterokinase Activity Assay Kits Ultra-sensitive

AnaSpec, EGT Group is pleased to announce the release of two assay kits for quantitating enterokinase enzymatic activity the SensoLyte 520 and SensoLyte Rh110 Enterokinase Activity Assay Kits. The former is a FRET (fluorescence resonance energy transfer)-based assay employing a novel internally quenched 5-FAM/QXL 520 substrate and the latter, an internally quenched fluorimetric peptide substrate. Both substrates emit at 520 nm with excitation at 490 nm. At the long emission wavelength of 520 nm, autofluorescence of components in biological samples and test compounds is minimal, thus making the kits ultra-sensitive. Assays are performed in a convenient 96-well microplate format.

Enterokinase or enteropeptidase 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.1,2 Enterokinase is a key enzyme for intestinal digestion of proteins. Its deficiency may cause severe protein malabsorption leading to impaired development and growth.3 Enterokinase also plays an important role in acute experimental and clinical pancreatitis.4 The high degree of specificity exhibited by enteropeptidase for cleaving affinity or other tags from recombinant proteins makes it an ideal tool for use in biochemical applications.5,6

SensoLyte 520 Enterokinase Activity Kit Cat# AS-72209

SensoLyte Rh110 Enterokinase Activity Kit Cat# AS-72210


FRET based 5-FAM/QXL 520

Fluorimetric, Rh110


490/520 nm

490/520 nm


1.25 ng/ml of active enzyme

0.3 ng/mL of active enzyme

Figure 1. Sensitivity of the SensoLyte 520 Enterokinase assay has been tested using serial dilution of bovine enterokinase. 5-FAM/QXL 520 FRET substrate was incubated with the indicated amount of enzyme and fluorescence was measured after 1 hour (FlexStation 384II, Molecular Devices). The assay can detect as low as 1.25 ng/mL of active enzyme.

Figure 2. Inhibition of enterokinase activity by E-64 was measured with SensoLyte520 Enterokinase Activity Assay Kit.


Catalog #

SensoLyte 520 Enterokinase Activity Assay Kit *Fluorimetric*


SensoLyte Rh110 Enterokinase Activity Assay Kit *Fluorimetric*


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1. Light, A., and Janska, H. Trends Biochem Sci 14, 110 (1989).
2. Zheng, XL., et al. Front Biosci (Elite Ed.) 1, 242 (2009).
3. Antonowicz, I., Ciba Found Symp 70, 169 (1979).
4. Mann, NS. and Mann, SK. Proc Soc Exp Biol Med 206, 114 (1994).
5. Forsberg, G. et al. J Protein Chem 11, 201 (1992).
6. Wang, Z. et al. Biol Chem 379, 167 (1998).