May be involved in fertilization (PubMed:21444326). Has no detectable bacteriolytic in vitro (PubMed:21444326). Has no lysozyme activity in vitro (By similarity). Monomer. Found in the principal piece of sperm tail (PubMed:21444326). Expressed strongly in testis and in epididymis, and weakly in brain and lung (PubMed:21444326, PubMed:24013621). Detected in sperm (at protein level) (PubMed:21444326). No expression in the testis of 2-weeks-old neonates, the expression reaches a peak level at 12 weeks. After that, the level gradually decreases as the age increases (PubMed:21444326, PubMed:24013621). Belongs to the glycosyl hydrolase 22 family. Although it belongs to the glycosyl hydrolase 22 family, Gly-72 is present instead of the conserved Asp which is an active site residue. It is therefore expected that this protein lacks hydrolase activity.