Matrix metalloproteinases and their inhibitors in connective tissue remodeling

Abstract

Matrix metalloproteinases are an important group of zinc enzymes responsible for degradation of the extracellular matrix components such as collagen and proteoglycans in normal embryogenesis and remodeling and in many disease processes such as arthritis, cancer, periodontitis, and osteoporosis. A matrixin family is defined, comprising at least seven members that range in size from Mr 28,000 to 92,000 and are related in gene sequence to collagenase. All family members are secreted as zymogens that lose peptides of about 10,000 daltons upon activation. Latency is due to a conserved cysteine that binds to zinc at the active center. Latency is overcome by physical (chaotropic agents), chemical (HOCl, mercurials), and enzymatic (trypsin, plasmin) treatments that separate the cysteine residue fr