Matrix metalloproteinases (MMPs) or matrixins may play a role in the degradation and remodeling of the extracellular matrix (ECM) during development or in response to stresses (By similarity). Active on myelin basic protein (MBP) and, to some extent, on McaPLGLDpaAR-NH(2) (QF24) and beta-casein (PubMed:24156403). Binds 1 zinc ion per subunit. Repressed by acetohydroxamic acid (AHA). Optimum pH is 5-9. Optimum temperature is 45-55 degrees Celsius. Mostly expressed in flowers and stems, and, to a lower extent, in leaves and roots. Starts to accumulate in 7-10 days old plant leaves. 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. Belongs to the peptidase M10A family. Matrix metalloproteinases (MMPs) subfamily.