Absolute bond dissociation energies of serine (Set) and threonine (Thr) to alkali metal cations are determined experimentally by threshold collision-induced dissociation of MIAA complexes, where M1 = Lil, Na', and KI and AA = Ser and Thr, with xenon in a guided ion bearn tandem mass spectrometer. Experimental results show that the binding energies of both amino acids to the alkali metal cations are very similar to one another and follow the order of Lil > Nal > K1. Quantum chernicat calculations at three different levels, B3LYP, WPM, and MP2(full), using the 6-31 I+G(2d,2p) basis set with geometries and zero-point energies calculated at the B3LYP/6-31 I +G(d,p) level show good agreement with the experimental bond energies. Theoretical calculations show that all MIAA complexes have charge-solvated structures (nonzwitterionic) with [CO, N, 01 tridentate coordination.