TNO211 is a bioactive peptide that functions as a highly soluble fluorogenic substrate for select Matrix Metalloproteinases (MMPs)—specifically MMP-2, 8, 12, 13, and 14. Incorporating a cleavable Gly-Leu bond and an EDANS/DABCYL fluorophore/quencher pair, TNO211 enables sensitive detection of MMP activity through fluorescence assays, with an absorption/emission profile at 340/490 nm. It is particularly effective in analyzing MMPs in culture media from endothelial cells as well as untreated synovial fluid from patients, highlighting its utility in investigations of MMP-associated cellular behaviors, including proliferation, migration (adhesion/dispersion), differentiation, angiogenesis, apoptosis, and host defense.