Based on limited published evidence, PRSS38 is a serine-type endopeptidase involved in proteolysis. Recently, PRSS38 was identified as a novel GPI-anchored sperm serine protease with a catalytic triad (His-100, Asp-150, Ser-245) 1. It localizes to the acrosomal region, equatorial segment, and flagellum in human sperm, with expression also detected in mouse spermatozoa. Functional studies demonstrate PRSS38's critical role in fertilization: antibody inhibition impaired human sperm-oocyte interactions and mouse in vitro fertilization 1. Genetic variants affecting catalytic and GPI-anchor residues exist in human populations, potentially altering protease function and contributing to male infertility.