<p>Nature Chemical Biology, Published online: 10 March 2026; <a href="https://www.nature.com/articles/s41589-026-02155-8">doi:10.1038/s41589-026-02155-8</a></p>Although long considered to be structured as oligomers comprising a single species, recent work highlights the ability of eukaryotic type 1 peroxiredoxin isoforms to assemble as heterodimers and heterodecamers in vivo. This key property redefines the current understanding of the biological scope of peroxiredoxins.