Disclosed is an isolated matrix metalloproteinase 9 (MMP9) binding protein, comprising: an immunoglobulin heavy chain polypeptide, or functional fragment thereof, and an immunoglobulin light chain polypeptide, or functional fragment thereof, wherein the MMP9 binding protein competes for binding to an epitope of human MMP9 comprising amino acid residues R162, E111, D113, and I198 with an antibody or antigen binding fragment thereof that binds MMP9.
