Matrix metalloproteinases (MMPs) are a family of at least 20 structurally related, zinc-containing enzymes that have the ability to breakdown connective tissue. MMP-3, also known as stomelysin-1 and transin, belongs to the stromelysin group of MMP�s which also includes MMP-10. MMP-3 has shown direct and indirect substrate specificity to collagens III, IV, V and IX, gelatins, fibronectin, fibrinogen, plasminogen, proteoglycans, elastin, casein, entactin, myelin basic protein, IL-1b, serum amyloid A, TIMP-2, MMP-1, MMP-7, MMP-8, MMP-9, and MMP-13. 1-17