Cyclic voltammetry: A new strategy for the evaluation of oxidative damage to bovine insulin

Research on protein oxidative damage may give insight into the nature of protein functions and pathological conditions. In this work, the oxidative damage of bovine insulin on Au electrode was investigated by cyclic voltammetry (CV). The experimental results show that there are two anodic peaks for the oxidative damage of bovine insulin, which arise from the oxidation of the exposed disulfide bond S? S_CYS7A,CYS7B, forming sulfenic acid RSOH (1.20 V, vs. SCE), sulfinic acid RSO₂H and sulfonic acid RSO₃H (1.35 V, vs. SCE). These in vitro findings not only demonstrate the applicability of CV in simulating/evaluating the oxidative damage of nonredox proteins but also find two promising candidates (two anodic peaks) for measuring insulin.