Metalloprotease that may play a role in the degradation of COMP. Binds 1 zinc ion per subunit. pH dependence: Optimum pH is between 7.5 and 9.5. [Subcellular location] Secreted, extracellular space, extracellular matrix (By similarity). Note=Also found associated with the external cell surface[Tissue specificity] Expressed in heart, brain, placenta, lung, liver, skeletal muscle, kidney and pancreas. Detected in meniscus, bone, tendon, cartilage, synovium, fat and ligaments. Up-regulated in articular cartilage and synovium from arthritis patients.