Peroxidases have been detected in the membrane of the ejaculated normal spermatozoon; their distribution on the different zones of the gamete has been determined. This distribution is similar to that of the N-linked glycoprotein-containing oligosaccharides. Their resemblance and similarity to the plant peroxidases, which are glycoproteins with N-type oligosaccharides, suggest that the sperm peroxidases might be, at least partially, identical to concanavalin A (Con A) and wheat germ lectin glycoprotein-containing receptors.

Similar locations of the Con A and wheat germ lectin receptors were obtained by using fluorescent lectins, in nonfixed spermatozoa and in spermatozoa fixed with formaldehyde and methanol, showing that in samples with the same previous treatment, worked out by the same operator, in which enough determinations have been performed to eliminate individual variations, the different procedures of fixation produced similar results. The locatizations obtained with fluorescent lectins confirm previous results, produced with the peroxidase technique, indicating that the lectins interact with oligomannosidic oligosaccharide receptors situated mainly in the equatorial segment of the acrosome and postnuclear cap. They also indicate the presence of similar receptors that were not detected previously on the neck and intermediate segment. The larger size of the lectin-peroxidase-diaminebenzidine reagent compared to that of the fluorescent lectins suggests that the new receptors are semicriptic and were not detected by steric effects in the first case, but were able to interact with lower volume, fluorescent probes. It is suggested that these oligomannosidic chains could be recognition signals for the elimination of incompetent sperm during their passage through the female reproductive track. Also these oligosaccharides and its possible metabolic variations could be involved in the interaction between the acrosome-reacted spermatozoa with the zone pellucida.