Peroxiredoxins are ubiquitous antioxidant proteins that form a plethora of protein architectures: from monomers and dimers to toroids of different subunit composition. Human peroxiredoxin 3 (hPrx3) exists in an equilibrium between a dodecameric toroid and a homodimer; this equilibrium being influenced by its redox state. hPrx3 predominantly targets H₂O₂ and is crucial for cellular antioxidant defence.

The dynamic structural state of peroxiredoxin may play a role in its activity. To investigate this, a point mutation, S75E, was made at the dodecamer-building interface, creating a homodimeric species that has been confirmed using CD, SEC-MALS and SAXS. Competitive kinetics with horseradish peroxidase have shown that this mutant is indeed active. This has implications for understanding the importance of oligomeric state for function of these abundant antioxidant proteins.