3-Deoxygluconsne（3-DG）, an α, β-dicarbonyl compounds in phosphate buffer, pH7.4 with amino acids, produced different ESR spectra depending on the added amino acids, by the use of 3,5-dibromo-4-nitrosobenzenesulfonic acid（DBNBS）which is suitable for spin trapping of carbon centered radicals. 3-DG is known to polymerize protein, but added Lys promoted the dimerization of lysozyme by the involvement of radical generation. As the formation and accumulation of α, β-dicarbonyl compounds is known as carbonyl stress, we proposed that these radicals derived from amino acid via Maillard reaction may contribute oxidative stress, main part of carbonyl stress.