Quantum chemical calculations have been carried out to investigate the interaction motifs of H2O2 with polar amino acid residues. Binding energies obtained from gas phase and continuum solvent phase calculations range between 2 and 30 kcal/mol. H2O2 interacts with the side chain of polar amino acids chiefly through the formation of hydrogen bonds. The -CH group in side chains of a few residues provides additional stabilization to H2O2. (C) 2014 Elsevier B. V. All rights reserved.