Plays a role in the degradation of extracellular matrix proteins including fibrillar collagen, fibronectin, TNC and ACAN. Cleaves several types of triple helical collagen. May also function by activating or degrading key regulatory proteins. Plays a role in wound healing, tissue remodeling, cartilage degradation, bone development, bone mineralization and ossification (By similarity). Can bind about 5 Ca(2+) ions per subunit. Binds 2 Zn(2+) ions per subunit. Up-regulated by thyroid hormone in tadpoles during tail resorption. The C-terminal region binds to collagen. 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 (By similarity). The proenzyme is activated by removal of the propeptide; this cleavage can be effected by other matrix metalloproteinases and may involve several cleavage steps. Cleavage can also be autocatalytic, after partial maturation by another protease or after treatment with 4-aminophenylmercuric acetate (APMA) (in vitro) (By similarity). The Xenopus genome contains two genes coding for very similar enzymes: MMP-13 and MMP-13A. Belongs to the peptidase M10A family.