This kit is designed to monitor the activity of an MMP-3 enzyme. The poptide sequence used in the kit is more selective for MMP-3 hydrolysis than other MMP enzymes. It can also be used to screen MMP-3 inhibitors when a purified MMP-3 enzyme is used. With excellent fluorescence quantum yield and longer wavelength, TF2 shows less interference from autofluorescence of test compounds and cellular components and is much more sensitive than an EDANS/Dabcyl FRET substrate. The assay can be performed in a convenient 96-well or 384-well microtiter-plate format. Its signal can be easily read by a fluorescence microplate reader at Ex/Em = 490/525 nm. The perfect excitation of TF2 at 488 nm makes the assay readily readable with almost all the common fluorescence instruments equipped with Argon laser and FITC filter set.