Abstract: We studied the aspartic acid (Asp) damage induced by αHatom abstraction of hydroxyl radicals assisted with water molecules in water gas phase and water liquid phase environment by using the dispersion correction density functional WB97XD method, the ab initio MP2 method and the slovation model density (SMD) model method of selfconsistent reaction field theory.  The results show that there are two channels a and b in the damage reaction of Asp. In channel a, hydroxyl radicals water clusters interact with αH and amino nitrogen to form the complexes damage through hydrogen bonding, and in channel b, hydroxyl radicals water clusters interact with αH and carbonyl oxygen to form the complexes damage through hydrogen bonding, this channel is the dominant channel, and the activation energies are -0.7,18.7 kJ/mol in 
water gas phase and water liquid phase environment, respectively. There is one channel in the reaction of Asp damage induced by αHatom abstraction of hydroxyl radicals, and the activation energies are 8.1 and 29.9 kJ/mol in water gas phase and water liquid phase environment, respectively.

Key words: aspartic acid, damage, hydroxyl radical, density functional theory, ab initio, SMD model, activation energy