Sperm surface membrane protein that may be involved in sperm- egg plasma membrane adhesion and fusion during fertilization. It could be a potential receptor for the egg oligosaccharide residue N- acetylglucosamine, which is present in the extracellular matrix over the egg plasma membrane. The processed form has no detectable bacteriolytic activity in vitro. . This is the function of SPACA3 (sperm acrosome associated 3, Ensembl gene identifier ENSG00000141316).