The matrix metalloproteinases (MMP) are a family of peptidase enzymes responsible for the degradation of extracellular matrix components，including collagen，gelatin，fibronectin，laminin and proteoglycan. MMP-17 (also designated MT-MMP4 or MT4-MMP) is a glycosylphosphatidylinositol (GPI)-anchored proteinase and is mainly expressed in the brain，leukocytes，colon，ovary and testis.
