Glutathione peroxidase-like protein that protects cells during oxidative stress. Has peroxidase activity reducing hydrogen peroxide, alkyl and phospholipid hydroperoxides using preferentially thioredoxin as a reducing power. May act as a scavenger of H(2)O(2). [thioredoxin]-dithiol + a hydroperoxide = [thioredoxin]-disulfide + an alcohol + H2O Monomer. By oxidative, osmo- and heat stress. The active site is a conserved redox-active cysteine residue, the peroxidatic cysteine (C(P)), which makes the nucleophilic attack on the peroxide substrate. The peroxide oxidizes the C(P)-SH to cysteine sulfenic acid (C(P)-SOH), which then reacts with another cysteine residue, the resolving cysteine (C(R)), to form a disulfide bridge. The disulfide is subsequently reduced by an appropriate electron donor to complete the catalytic cycle. In this atypical 2-Cys peroxiredoxin, C(R) is present in the same subunit to form an intramolecular disulfide. Belongs to the glutathione peroxidase family. Was originally thought to be a glutathione peroxidase (PubMed:10455235), but functions as an atypical 2-Cys peroxiredoxin using thioredoxin as reducing power instead (PubMed:18162174).