背景资料:Matrix metalloproteinases (MMPs) are a family of at least 23 structurally related, zinc-containing enzymes that have the ability to breakdown connective tissue. MMP-1 has shown substrate specificity to collagens types I, II, III, VII, VIII, X, and XI as well as additional extracellular matrix components including gelatin, fibronectin, laminin, and proteoglycan.