Fig. 2.

Interconnection of glutaredoxin, peroxiredoxin, thioredoxin, and glutathione containing antioxidant systems. Hydrogen peroxide (H₂O₂) can be reduced by peroxiredoxins (Prx) or glutathione peroxidases (GPX), which couple reduction of H₂O₂ with oxidation of glutathione (GSH). Oxidized Prx can be reduced by thioredoxins (Trx). Subsequently, oxidized Trx become reduced by thioredoxin reductase (TrxR) in a NADPH-dependent manner. Oxidized glutathione disulfide (GSSG) is reduced by glutathione reductase (GR) in the presense of NADPH. Further, glutaredoxins (Grx) can reduce disulfide (S–S) bonds in proteins (Pr), and glutathione S transferase (GST) is using GSH to conjugate and thus to detoxify reactive electrophilic compounds (R).