Thiol-specific peroxidase that catalyzes the reduction of hydrogen peroxide and organic hydroperoxides to water and alcohols, respectively. Plays a role in cell protection against oxidative stress by detoxifying peroxides. [thioredoxin]-dithiol + a hydroperoxide = [thioredoxin]-disulfide + an alcohol + H2O Homodimer; disulfide-linked, upon oxidation. Up-regulated by high-intensity light and H2O2 (Ref.1). Down-regulated in the late stationary growth phase as compared to the early stationary and exponential growth phases (PubMed:23291769). Belongs to the peroxiredoxin family. AhpC/Prx1 subfamily.