Anti-sperm adhesion molecule 1 (PH-20 hyaluronidase, zona pellucida binding) antibodies are protein reagents that detect specific antigens. The sperm adhesion molecule 1 (PH-20 hyaluronidase, zona pellucida binding) antigen is another term for the human protein sperm adhesion molecule 1, encoded by the SPAM1 gene. The protein is known to be involved in sperm-egg adhesion. Canonically, it has an amino acid length of 509 residues and a mass of 57.8 kilodaltons. Its subcellular localization is in the cell membrane and it is notably expressed in the testis. The sperm adhesion molecule 1 (PH-20 hyaluronidase, zona pellucida binding) protein is a member of the Glycosyl hydrolase 56 protein family. Other alias names for sperm adhesion molecule 1 (PH-20 hyaluronidase, zona pellucida binding) include HEL-S-96n, HYA1, and HYAL1.