Matrix metalloproteinase that plays an essential role in local proteolysis of the extracellular matrix and in leukocyte migration (By similarity). Could play a role in bone osteoclastic resorption (By similarity). Cleaves KiSS1 at a Gly-|-Leu bond (By similarity). Cleaves NINJ1 to generate the Secreted ninjurin-1 form (By similarity). Cleaves type IV and type V collagen into large C-terminal three quarter fragments and shorter N-terminal one quarter fragments. Degrades fibronectin but not laminin or Pz-peptide (By similarity). Cleavage of gelatin types I and V and collagen types IV and V. Binds 2 Zn(2+) ions per subunit. Binds 3 Ca(2+) ions per subunit. Exists as monomer or homodimer; disulfide-linked. Exists also as heterodimer with LCN2. Macrophages and transformed cell lines produce only the monomeric form. Interacts with ECM1. The conserved cysteine present in the cysteine-switch motif binds the catalytic zinc ion, thus inhibiting the enzyme. The dissociation of the cysteine from the zinc ion upon the activation-peptide release activates the enzyme. N- and O-glycosylated. Belongs to the peptidase M10A family.