May be involved in sperm maturation and/or fertilization. May also be involved in epithelia functions associated with establishing and maintaining gradients of ions or nutrients. Binds 1 zinc ion per subunit. A tripeptide motif (VGE) within disintegrin-like domain could be involved in the binding to egg integrin receptor and thus could mediate sperm/egg binding. The cysteine-rich domain encodes putative cell-fusion peptides, which could be involved in sperm-egg fusion. 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. Has no obvious cleavage site for furin endopeptidase, suggesting that the proteolytic processing is regulated. May be the functional equivalent of ADAM 1/fertilin alpha which is a pseudogene in human.