Summary. The in-vitro proteolytic activity of boar sperm acrosin was stimulated by a series of monovalent and divalent metal ions. Equivalent concentrations of monovalent cations resulted in nearly identical increases in proteolytic activity, probably related to the increased ionic strength of the incubation medium. However, at concentrations of monovalent cations that resulted in a 2- to 3-fold stimulation of proteolysis of Azocoll, divalent metal ions caused a 24-(magnesium) to 46-(calcium) fold increase in proteolytic activity. We suggest that the divalent metal ion binds to acrosin and thus increases the proteolytic activity of acrosin to an extent greater than that due to the increased ionic strength of the incubation medium.
R. F. Parrish and K. L. Polakoski
R. F. Parrish, J. C. Goodpasture, L. J. D. Zaneveld and K. L. Polakoski
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.