Mca-Lys-Pro-Leu-Gly-Leu-Dap(Dnp)-Ala-Arg-NH2 (FS-6) is a fluorescent peptide that is a quenched MMP peptide substrate. Mca-Lys-Pro-Leu-Gly-Leu-Dap(Dnp)-Ala-Arg-NH2 can be used for real-time quantification of MMP enzymatic activity. Mca-Lys-Pro-Leu-Gly-Leu-Dap(Dnp)-Ala-Arg-NH2 is an elongated peptide of MMP substrate (FS-1) and is active against collagenases (MMP-1, MMP-8, MMP-13 ) and MT1-MMP with higher specificity constants than FS-1. (Ex/Em=325 nm/400 nm)