FIG 5.

Iron species decompose H₂O₂ directly. LB broth containing 200 μM H₂O₂ was mixed with the indicated chemicals at various concentrations. After 30 min of incubation, the amount of H₂O₂ remaining was determined using the LCV method. The data were normalized to the initial concentration. The concentrations of the chemicals tested in the assay were as follows: Fe²⁺, 0.02 to 0.2 mM; Fe³⁺, 0.2 to 1 mM; thiourea, 0.1 to 2 mM; and Mn²⁺, 0.4 to 2 mM. The data reported represent the mean results ± SD (n = 4).