MMP-1 (interstitial collagenase, fibroblast collagenase) is an extracellular protease. This enzyme plays a significant role in cancer, arthritis and other diseases, and has been identified as a drug-screening target. The SensoLyte® 520 MMP-1 Assay Kit uses a 5-FAM (fluorophore) and QXL520™ (quencher) labeled FRET peptide substrate for continuous measurement of enzyme activity. In an intact FRET peptide, the fluorescence of 5-FAM is quenched by QXL520™. Upon the cleavage of the FRET peptide by MMP-1, the fluorescence of 5-FAM is recovered, and can be continuously monitored at excitation/emission = 490 nm/520 nm. With superior fluorescence quantum yield and longer emission wavelength, 5-FAM/QXL520™ based FRET peptide has less interference from the autofluorescence of test compounds and cellular components and provides better assay sensitivity. The assays are performed in a convenient 96-well or 384-well microplate format. Members of the MMP family have poor substrate sequence specificity, making it difficult to use a peptide substrate alone to differentiate the activity of a particular MMP from other MMPs. If several MMPs are coexisting in your samples and you would like to specifically measure MMP-1 activity, please choose the SensoLyte® Plus MMP-1 Assay Kit, Cat# 72012.