Summary. The conversion of human proacrosin to acrosin was inhibited by polyamines. The order of effectiveness was spermine > spermidine > cadaverine > putrescine > 1,3-diaminopropane. These results are similar to those obtained for the conversion of boar proacrosin to acrosin. Unlike the effects on boar acrosin, however, polyamines did not affect the esterolytic activity of human acrosin but had a slight stimulatory effect on the proteolytic activity of human acrosin.
R. F. Parrish, J. C. Goodpasture, L. J. D. Zaneveld and K. L. Polakoski
Jessie C. Goodpasture, P. M. Zavos, M. R. Cohen and L. J. D. Zaneveld
Summary. Stability of the human sperm acrosin system (major components: non-zymogen acrosin, proacrosin and acrosin inhibitor) was studied under various conditions of semen storage used clinically or in the laboratory. Freezing at −196°C caused a profound decrease in total acrosin content and in the amount of this enzyme present in zymogen form (proacrosin), but resulted in some increase in non-zymogen acrosin. Acrosin inhibitor did not appear to be significantly affected by this treatment. No relationship was present between the decreases in sperm motility induced by freezing to −196°C and the alterations in total acrosin, proacrosin and non-zymogen acrosin.
Storage of whole semen at −20°C had deleterious effects on all the components of the acrosin system measured except for non-zymogen acrosin. Major decreases in the total acrosin, proacrosin and acrosin inhibitor occurred after only 1 day at −20°C and continued slowly thereafter. Whole semen kept at room temperature for up to 24 h after ejaculation did not show any significant changes in the sperm acrosin system. Seminal plasma did not have a detrimental or stabilizing effect on acrosi[ill] and proacrosin when spermatozoa were kept at room temperature. However, removal of seminal plasma and re-suspension of spermatozoa in 0·9% NaCl resulted in the liberation of a significant amount of the acrosin inhibitor from the spermatozoa and the apparent activation of some of the proacrosin to acrosin.