May play a role in organogenesis and organ-specific functions such as thymic T-cell development. Binds 1 zinc ion per subunit. Additional isoforms seem to exist. Strong expression in thymic epithelial cells and developmentally related tissues including the trachea, thyroid, lung and stomach, but not in lymphocytes. Expressed at high levels also in epididymis. In contrast with human is not expressed in immature or mature lymphocyte populations of thymocytes, lymph node, spleen, and bone marrow. The expression patterns in adult and day 15.5 embryos are similar. 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.