MMP-3 is a member of matrix metalloproteinase family proteins (MMPs); members of this family are structurally related, zinc-containing enzymes that degrade the extracellular matrix (ECM) and connective tissue proteins in normal physiological processes such as embryonic development, reproduction, and tissue remodeling as well as in disease processes such as arthritis and metastasis. MMP-3 consists of a prodomain which is cleaved upon activation, a catalytic domain containing the zinc binding site, a short hinge region, and a carboxyl terminal (hemopexin-like repeats) domain. Substrates of MMP-3 include collagen α chains, aggrecan, laminin, fibronectin, elastin, casein, α1-antitrypsin, myelin basic protein, IL1β, IGFBP3, pro MMP1, pro MMP7, pro MMP8, pro MMP9, and pro MMP13. MMP-3 is thought to be involved in wound repair, progression of atherosclerosis, and tumor initiation. It has also been known that a polymorphism in the MMP3 promoter region is associated with the risk of coronary heart disease and myocardial infraction due to lower MMP3 proteolytic activity and higher ECM deposition in atherosclerotic lesions.