In this manuscript, we used light scattering, AFM, mass spectrometric, and isothermal titration calorimetric methods to show that excess cupric ions mediates oxidation of Cys-111 and leads to aggregate formation of ALS-associated SOD1 mutant A4V and wild-type SOD1 oxidized by hydrogen peroxide under copper-mediated oxidative conditions. This evidence concerns the gene SOD1 and amyotrophic lateral sclerosis.