Cisplatin was studied for its effect on the copper-catalyzed oxidation of amyloid beta (A beta) peptide. The interaction of cisplatin with A beta 1-16 in the presence of Cull was investigated using cyclic voltammetry and mass spectrometry. The positive shift in the E-1/2 value of A beta 1-16-Cu-II suggests that the interaction of cisplatin alters the copper-binding properties of A beta 1-16. The mass spectrometry data show complete inhibition of copper-catalyzed decarboxylation/deamination of the Asp1 residue of A beta 1-16, while there is a significant decrease in copper-catalyzed oxidation of A beta 1-16 in the presence of cisplatin. Overall, our results provide a novel mode by which cisplatin inhibits copper-catalyzed oxidation of A beta. These findings may lead to the design of better platinum complexes to treat oxidative stress in Alzheimer's disease and other related neurological disorders.