Metalloproteases in connective tissue degradation
Metalloproteases in connective tissue degradation Remodeling of extracellular matrix is possible due to activity of specific, skilledproteolytic enzymes present in connective tissue. Most proteolytic enzymes aremetalloproteinases. Metalloproteinases (MMPs) are involved in most of physiological andpathological processes in human body, such as the embryonic development and growth,tissue remodelling and repair,as well as digestion. Under normal conditions, MMPs arepresent in tissues at low levels that increase dramatically during any changes , . Overexpression and activation of proteinases destroy theconnective tissue and contribute to many pathologies, e.g., arthritis ,cardiovascular disease , tumour progression  and lungdisease , Although similarities exist in the structure of the MMPs, there are also distinctdifferences in the recognition and specificity for components of the extracellular matrix. Currently, the MMP family encompasses at least 25 related proteolyticenzymes that include four broad classes: the collagenases (e.g., MMP-1,MMP-13 ), gelatinases (e.g., MMP-2, MMP-9 ), stromelysins (e.g.,Matrix metallopeptidases 3 and 10 ( Stromelysin-1 and Stromelysin-2 ), andmembrane type enzymes (e.g., MMP-14, MMP-15, MMP-17 ). However,there are a number of family members that are classified outside of these four broadclasses .