May play a role in the adhesive and proteolytic events that occur during lymphocyte emigration or may function in ectodomain shedding of lymphocyte surface target proteins, such as FASL and CD40L. May be involved in sperm maturation. Binds 1 zinc ion per subunit. Expressed at high levels in epididymis and at lower levels in lung. 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. Pro-domain removal and maturation may be, at least in part, autocatalytic.