Prxs are thought to be the major scavengers of H2O2 in cells [ 2 4 ]. Peroxiredoxin genes are present in nearly all previously characterized organisms, suggesting that these enzymes serve important functions conserved throughout evolution [ 2 ]. In addition to antioxidant function, peroxiredoxins are implicated in cell signaling due to their ability to reduce intracellular levels of hydroperoxides and to serve as floodgates of H2O2 signaling, which posits that Prx inactivation enables peroxide-mediated signaling in eukaryotes