Mca-Ala-Pro-Lys(Dnp)-OH（Cat No.:I031649）is a fluorogenic peptide substrate commonly used to measure protease activity, particularly for enzymes like matrix metalloproteinases (MMPs) and other serine proteases. It contains a 7-methoxycoumarin-4-acetyl (Mca) fluorophore at the N-terminus and a 2,4-dinitrophenyl (Dnp) quencher on the ε-amino group of lysine. In its intact form, fluorescence is quenched; upon enzymatic cleavage, the fluorophore is released, resulting in increased fluorescence. This substrate enables sensitive, real-time detection of enzymatic activity in biochemical assays, making it a valuable tool for drug screening, enzyme kinetics, and protease inhibitor studies.