Synonyms:SPAM1, HEL-S-96n, HYA1, HYAL1, HYAL3, HYAL5, PH-20, PH20, SPAG15, hyaluronidase PH-20 Background:Involved in sperm-egg adhesion. Upon fertilization sperm must first penetrate a layer of cumulus cells that surrounds the egg before reaching the zona pellucida. The cumulus cells are embedded in a matrix containing hyaluronic acid which is formed prior to ovulation. This protein aids in penetrating the layer of cumulus cells by digesting hyaluronic acid.