Only a very small portion (4–7%) of the hyaluronidase of rat sperm obtained from the caput or cauda epididymis was released during incubation in capacitation medium for up to 24 h at 37°C. A portion of the cell‐associated hyaluronidase was accessible to external substrates, allowing sperm suspensions to lyse glycosaminoglycans of cumulus clots rapidly, even without capacitation. This process appears to represent the employment of an enzyme bound to the sperm cell, analogous to the use of solid‐phase enzymes in current enzyme tech