To assess to what extent the way the protein backbone is modeled influences the computed BDEs, we compared BDEs of the C α atom with varying capping groups. The way the protein backbone is modelled can be expected to have a particularly strong influence on the C α -H BDEs, not only because of the close proximity of the C α -H bond to the capping groups, but also because its radical is captodatively stabilized by the backbone amide groups. C α -H BDEs of glycine and alanine were calculated with three different types of capping groups: without, with smaller capping groups corresponding to the next backbone atom, and with larger capping groups corresponding to the next two backbone atoms. Calculations were performed using BMK/6-31+G(2df,p)