Beta-Ala-R110-ML

Fluorometric methods based on the peptide substrates labeled with cleavable fluorophores have been widely used for assaying various proteases. The two dominant classes are AMC-based (coumarin dye) and R110-based (rhodamine 110) substrates. AMC substrates are much less sensitive due to their short wavelength, low extinction coefficient and high fluorescent background resulted from the autofluorescence of biological samples. R110-based peptide substrates have a longer excitation and emission wavelength, low background signal, and being highly fluorescent. However, R110-based peptide substrates carries two peptide blocking groups that need to be cleaved from their bis-peptide substrates in order to generate maximal signal. This two-step cleavage severely limits the linear dynamic range of R110-based peptide substrates. N-morpholinecarbonyl-R110 (R110-ML) has been successfully used to overcome both the poor cell penetration and the kinetic limitation of R110-based peptide substrates. R110-ML substrates are as sensitive as R110 substrates for most of protease detections. Beta-Ala-R110-ML is a fluorogenic substrate that might be used for detecting aminopeptidase M substrate, alanyl aminopeptidase and trypsin activities. Beta-Ala-R110-ML may be used for detecting some bacteria in food and other samples by monitoring their alanyl aminopeptidase activities. Compared to Ala-AMC (#13458), Beta-Ala-R110-ML is more sensitive. Its enzymatic product can be readily detected with the common FITC channel or FITC filter set.