SPAM1 Proteins and Enzymes

SPAM1 (Sperm adhesion molecule 1), also known as PH-20 hyaluronidase, is a GPI‑anchored enzyme located on the sperm surface and inner acrosomal membrane. SPAM1 degrades hyaluronic acid (HA), a major structural glycosaminoglycan found in extracellular matrices and basement membranes. The enzyme activity enables sperm to penetrate through the HA-rich cumulus cell layer surrounding the oocyte and therefore facilitates the fertilization process.