FIG. 5.

Effect of assay conditions on Lfcin and aLf activity. (A) Lfcin B is active in dH₂O but not in PBS. S. aureus Newman was incubated with Lfcin B in PBS (▪) and dH₂O (⧫). (B) aLf (0.5 μM) is active in PBS but only poorly active in dH₂O. S. aureus Newman was incubated with human (▪ and □) or bovine (▴ and ▵) aLf. Filled symbols, incubation in PBS; open symbols, incubation in dH₂O. The data are the means of three independent experiments. (C) Serine protease activity of aLf is bactericidal. S. aureus Newman was incubated with 0.5 μM human aLf (▪ and □) and 0.5 μM bovine aLf (▴ and ▵). Some preparations were pretreated with PMSF (open symbols). The values are the means of three independent experiments.