Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that degrade substances within the extracellular matrix. The MMP family includes six different groups of enzymes: collagenases, gelatinases, stromelysins, transmembrane MMPs, matrilysins and others. MMPs are secreted as proenzymes that have to be cleaved in order to be activated. Other MMPs, plasmins as well as other factors activate MMPs. MMPs are thoμght to play an important role in tissue remodeling associated with various physiological and pathological processes. MMP1 cleaves collagens of types I, II, III, VII and X.  MMP1 is thoμght to play an important role in rheumatoid and osteo-arthritis pathogenesis as mediators of cartilage and bone destruction.