Matrix Metalloproteinases (MMPs) are a large family of endopeptidases. Collectively, MMPs can degrade all kinds of extracellular matrix proteins, and can also process a number of bioactive molecules. They are known to be involved in the cleavage of cell surface receptors, the release of apoptotic ligands, and chemokine/cytokine inactivation. MMPs are also thought to play a major role in cell behaviors such as cell proliferation, migration (adhesion/dispersion), differentiation, angiogenesis, apoptosis, and host defense. NFF-3 is hydrolyzed rapidly by MMP-3 (kcat/Km = 218,000 s-1 M-1) and very slowly by MMP-9 (kcat/Km = 10,100 s-1 M-1), but no significant hydrolysis by MMP-1 and MMP-2. It is one of the few synthetic substrates selectively hydrolyzed by certain members of the MMP family and thus has important applications for the differentiation of MMP-3 activity from that of other MMPs. Abs/Em = 325/393 nm.