Figure 1From: Articular cartilage and changes in Arthritis: Matrix degradationSchematic representation of the domain structure of the matrix metalloproteinases (MMPs) associated with cartilage degradation. The sequence HEXXH is a conserved motif in this family of metalloproteases. The two histidine residues (H) are ligands for the essential zinc ion, and the side chain of the glutamic acid (E) acts as a general base for peptide bond cleavage. MMP-1, -8, and -13, collagenases; MMP-3, stromelysin; MMP-2 and -9, gelatinases; MMP-7, matrilysin; MMP-14, membrane type metalloproteinase-1Back to article page