Sperm surface membrane protein that may be involved in sperm-egg plasma membrane adhesion and fusion during fertilization. Could have a direct role in sperm-zona binding or migration of sperm from the uterus into the oviduct. Interactions with egg membrane could be mediated via binding between its disintegrin-like domain to one or more integrins receptors on the egg. This is a non catalytic metalloprotease-like protein (By similarity). Heterodimer with ADAM1/fertilin subunit alpha. A tripeptide motif (NQE) within disintegrin-like domain could be involved in the binding to egg integrin receptor and thus could mediate sperm/egg binding. The prodomain and the metalloprotease domain are cleaved during the epididymal maturation of the spermatozoa.