Studies on the structure,states,and reactivity of excess electrons(EEs)in biological media are of great significance.Although there is information about EE interactions with dry biological molecules,solution effects are hardly explored.In this work,we present an ab initio molecular dynamics simulation study on the interaction and reactivity of an EE with amino acids in solution.Three representative amino acids are considered: glycine,lysine and aspartic acid.Our simulations reveal two striking results.Firstly,a pre-solvated EE partially localizes on the negatively charged-COO-group of the zwitterionic glycine and the remaining part delocalizes over solvent water molecules,forming an anion-centered quasi-localized structure,due to the relative alignment of the lowest unoccupied molecular orbital energy levels of the potential sites for EE residence in the aqueous solution.Secondly,after a period of anion-centered localization of an EE,the zwitterionic glycine is induced to spontaneously fragment through cleavage of the N-Cα bond,losing ammonia(deamination),and leaving a ·CH2-COO-anion radical,in good agreement with experimental observations.Introduction of the lysine and aspartic acid side chains can affect EE localization,with the fragmentation of the backbone part of these amino acids dependent on the properties of the side chain group.These findings provide insights into EE interaction mechanisms with amino acids and low energy EE induced fragmentation of amino acids,peptides,and proteins.