This Molecular Probes™ bisamide derivative of rhodamine 110 (R110) is a sensitive and selective substrate for assaying proteases in solution or inside living cells. These fluorogenic substrates contain an amino acid or peptide covalently linked to each of R110’s amino groups. Upon enzymatic cleavage, the nonfluorescent bisamide substrate is converted first to the fluorescent monoamide and then to R110, with a further increase in fluorescence. The substrate can be used to continuously measure enzyme activity in cell extracts and purified enzyme preparations using a fluorometer or fluorescence microplate reader, or can be used for intracellular protease assays with analysis by flow cytometry or fluorescence microscopy.

Substrate Specifications:
• Substrate name: (p-tosyl-Gly-Pro-Arg)₂-R110
• Useful to measure: Thrombin
• Ex/Em of R110 product: (498/521 nm)

Properties of the R110 Reaction Product
The R110 cleavage product has spectral properties similar to those of fluorescein, making it compatible with standard fluorescein filter sets. Because of the large extinction coefficient of R110, signal to background ratios are very good. And, unlike fluorescein, the fluorescence intensity of the rhodamine 110 reaction product is constant from pH 3–9. We also offer an R110 reference standard for use in your assays.

We’ll Make a Custom R110 Substrate for You
If you can’t find what you’re looking for in our stocked list, we’ll prepare a custom R110 substrate for you. Our custom services are efficient and confidential, and we stand by the quality of our work. We are ISO 13485:2000 certified.

For more information about these products, read Detecting Peptidases and Proteases—Section 10.4 in the Molecular Probes™ Handbook.

For Research Use Only. Not for human or animal therapeutic or diagnostic use.