Nature Communications, Published online: 20 August 2026; doi:10.1038/s41467-026-76384-9 Carboxylic acids are widely found moieties in feedstock chemicals as well as biomolecules, and as such, deuterations of scaffolds containing acid functionalities would be of synthetic use. Here the authors report a α-site-selective deuteration method that is compatible with both free amino acids and general (non-amino-acid) carboxylic acids enabled by a regenerable Pd1/CeOx single atom catalyst.