Figure 5.

p4 bacteriostatic activity depends on oxidation of cysteine residues of p4. A, E. coli HB101 was incubated with 1.5 μm of the indicated forms of p4 for 2 h. B, S. aureus 8325-4 was incubated with the indicated forms of p4 (6 μm) for 2 h. C, FITC-p4 was incubated without bacteria with NAC or H₂O₂, followed by analysis by SDS-PAGE. D, E. coli HB101 was incubated with 1.5 μm p4 and/or 1.8 mm NAC for 2 h. E, E. coli HB101 was incubated with 1 μm of the indicated forms of p4 and/or 5 μm H₂O₂ for 2 h. Cell viability, shown as the percentage of a vehicle-treated cells, was analyzed by MDA assay; n = 3, each experiment done in six replicates. Plots show individual data points and mean ± S.D. ***, p < 0.001; **, p < 0.01; ns, nonsignificant by Kruskal-Wallis one-way ANOVA with post hoc Dunn's test.