“…They reside in the acrosome and are believed to aid the spermatozoon to penetrate the surrounding cells and zona pellucida of the egg before fertilization. The enzymes found in this part of the mammalian (including human) spermatozoon include acid phosphatase, arylsulphatase, N-acetyl-/?-D-glucosaminidase, phospholipase A, proteases (Allison & Hartree, 1970;Teichman & Bernstein, 1971;Penn, Gledhill & Darzynkiewicz, 1972; Yanagimachi & Teichman, 1972), trypsin-like enzyme, 'corona-penetrating' enzyme, neuraminidase Pedersen, 1972;Polakoski, 1972) and hyaluronidase (Srivastava, Adams & Hartree, 1965). Acrosomal proteolytic activity has also been demonstrated in the spermatozoa of Rana pipiens .…”