FIG. 5.

Alpha-clostripain activities of various C. perfringens strains. (A) The alpha-clostripain activity of each C. perfringens strain (indicated at the bottom) was determined with azocasein as a substrate under conditions with no inhibitor (−), with leupeptin (LP), or with antipain (AP). For each strain and treatment combination, the mean absorbance and standard deviation (error bar) calculated from three independent experiments are shown. (B) The difference in mean proteolytic activity between assays without inhibitors and assays with the leupeptin or antipain inhibitor (shown in panel A), which represents alpha-clostripain-specific proteolytic activity, was plotted for each C. perfringens strain. WT, wild type; OD 450 nm, optical density at 450 nm.