Purification and properties of boar acrosin

An isolation procedure in the presence of non-ionic detergents has been developed for the large-scale preparation of boar acrosin. Five steps including hydrophobic interaction chromatography on phenyl-Sepharose resulted in a 161-fold purification of the enzyme with an accumulation yield of 41%. The resultant acrosin preparation had a molecular weight of 38,000, an isoelectric point of 10.5 and a specific activity of 37 U/mg. Apparent homogeneity was judged by sodium dodecyl sulfate electrophoresis and isoelectric focusing. A polarity index of 41.2% was calculated from the amino acid composition. Acrosin was stable at pH 5.5 in the presence of 0.1% Triton X-100. In the absence of detergent acrosin was strongly adsorbed on plastic surfaces.