Activation of chymotrypsinogen by boar acrosin and its prevention by antiboar acrosin rabbit gamma-globulins.

Activation of chymotrypsinogen by bovine trypsin or boar sperm acrosin was followed up using Nalpha-acetyl-L-tyrosine ethyl ester in a highly sensitive test system. Inhibition studies employing antiboar acrosin rabbit gamma-globulins showed the following results. 1) Whereas the acrosin-induced activation velocity was significantly depressed in the presence of the antibodies, the trypsin-catalyzed activation rate was not diminished. 2) The antibodies enhanced the acrosin-catalyzed cleavage rate of BzArgOEt significantly, but not the trypsin-catalyzed cleavage rate of this substrate. 3) Autodigestion of acrosin was considerably reduced in the presence of the antibodies. The enzymatic test system used is especially suitable to study the specificity of acrosin antibodies or their affinity to related enzymes if only small amounts of these substances are available.