Figure 5.

Model for the hierarchy of Prx resistance. Stratification of Prx susceptibility to hyperoxidation is shown. Low levels of H₂O₂ are associated with nonstress cell signaling, and high levels can lead to oxidative stress–induced signaling. The Prxs most sensitive to hyperoxidation in this study each contain only one resistance motif (Prx1, motif A; Prx2, motif B). Prx3 contains both motifs A and B and is more resistant than Prx1 and Prx2 but is not as resistant as AhpC. AhpC also contains both motifs A and B but lacks the YF and GGLG motifs. Based on the proposed grading of resistance, each eukaryotic Prx will be inactivated at a different threshold of H₂O₂ concentration, enabling a diversity of cellular responses.