Contributes to oxidative stress resistance by reducing cysteine-sulfinic acid formed under exposure to oxidants in a peroxiredoxin. May catalyze the reduction in a multi-step process by acting both as a specific phosphotransferase and a thioltransferase. Required to switch on the antioxidant pathway to regenerate the oxidative damage. In mitochondrion, catalyzes the retroreduction of the inactive sulfinic form of atypical Prx IIF using thioredoxin as reducing agent. [protein]-dithiol + ATP + S-hydroxy-S-oxy-L-cysteinyl-[peroxiredoxin] = [protein]-disulfide + ADP + phosphate + S-hydroxy-L-cysteinyl-[peroxiredoxin] kcat is 0.66 min(-1) with peroxiredoxin-(S-hydroxy-S-oxocysteine) as substrate (in the presence of 1 mM of ATP) and 0.025 min(-1) with ATP as substrate (in the presence of 40 uM of peroxiredoxin-(S-hydroxy-S-oxocysteine)). Optimum pH is 7.8. Additional isoforms seem to exist. Low expression in photosynthetic tissues such as leaves and sepals. Accumulation of overoxidized peroxiredoxin (Prx) and hyperoxidized form of Prx IIF, especially in response to photooxidative stress, H(2)O(2) treatment and water deficit. Increased tolerance to photooxidative stress generated by high light combined with low temperature. In long days, smaller leaves. Belongs to the sulfiredoxin family.