Comparative Studies of the Acrosomal Enzymes of Rabbit, Rhesus Monkey, and Human Spermatozoa1

Abstract

Methods are described for the isolation of subcellular fractions from rabbit, rhesus monkey, and human sperm using sucrose-density gradients. All three species were found to possess hyaluronidase and a specific trypsin-like enzyme in the head fractions from their spermatozoa. Both enzymes were further localized in the acrosomes in the rabbit and rhesus monkey, and were found to be present in a relatively constant ratio in all three species, although the specific activities do vary between species. A chymotrypsin like enzyme, present in ejaculated but not in the epididymal sperm, was extracted in the soluble portion of the spermatozoa and apparently originates by adsorption from the seminal plasma. The cyclic changes in human cervical mucus alpha₁-antitrypsin were found to be without any apparent physiologic function in relation to the acrosomal trypsin-like enzyme or the seminal plasma chymotrypsin-like enzyme, since the inhibitor was ineffective on both enzymes.