Hydroxyl radical (center dot OH) is known to be highly Asp oxidation mechanism reactive. Herein, we analyze the oxidation of acid (Asp and Glu), base (Arg and Lys), and amide (Asn and Gin) containing amino acid derivatives by the consecutive attack of two center dot OH. In this work, we study the reaction pathway by means of density functional theory. The oxidation mechanism is divided into two steps: (l) the first center dot OH can abstract a H atom or an electron, leading to a radical amino acid derivative, which is the intermediate of the reaction and (2) the second center dot OH can abstract another H atom or add itself to the formed radical, rendering the final oxidized products. The studied second attack of center dot OH is applicable to situations where high concentration of center dot OH is found, e.g., in vitro. Carbonyls are the best known oxidation products for these reactions. This work includes solvent dielectric and confirmation's effects of the reaction, showing that both are negligible. Overall, the most favored intermediates of the oxidation process at the side chain correspond to the secondary radicals stabilized by hyperconjugation. Intermediates show to be more stable in those cases where the spin density of the unpaired electron is lowered. Alcohols formed at the side chains are the most favored products, followed by the double-bond-containing ones. Interestingly, Arg and Lys side-chain scission leads to the most favored carbonyl-containing oxidation products, in line with experimental results.