Inactivation of Boar Acrosin by Peptidyl-arginyl-chloromethanes Comparison of the Reactivity of Acrosin, Trypsin and Thrombin

Abstract

A survey of the reactivity of 16 peptidyl-argininyl-chloromethanes with boar acrosin [EC 3.4.21.10] indicated that these compounds as a general group of reagents were highly effective in the inactivation of acrosin since at least half of the reagents tested rapidly inactivated this protease at a concentration of 0.10 .mu.M or lower. For example, Dns[1-(dimethylamino)naphthalene-5-sulfonyl]-Glu-Gly-ArgCH2Cl inactivates acrosin by 50% in 1.8 min at a concentration of 75 nM, whereas in contrast, a 14,000-fold higher concentration of N.alpha.-tosyllysyl-chloromethane is required to obtain an equivalent rate of inactivation. A comparison of the reactivity of acrosin and trypsin [EC 3.4.21.4] with the peptides of arginyl-chloromethane containing different substituents in the P2 and P3 positions suggests that the secondary binding sites of these 2 proteases are very similar. Reagents with homoarginine, lysine and D-arginine in the P1 position were also prepared and evaluated, but these were considerably less effective than the corresponding arginyl-chloromethanes in the inactivation of both acrosin and trypsin.