Investigating the Factors Influencing Oxidative Modification of Human Cytochrome c Using Girard's Reagent T as an NMR Probe

Oxidative modification of cytochrome c (Cyt c) may influence the local conformation of protein, yet the mechanism by which structural alterations of Cyt c affect its degree of oxidative modification remains unclear. In this study, Girard’s reagent T (GRT) was employed as a nuclear magnetic resonance (NMR) probe to investigate the oxidative modification levels of human Cyt c under varying environmental conditions. Experimental results demonstrated that protecting lysine residues through reductive methylation effectively reduced protein oxidation. Partial unfolding of Cyt c was found to enhance its oxidative modification, while binding Cyt c with cardiolipin significantly increased the extent of oxidation. Additionally, other factors such as protein aggregation exhibited inhibitory effects on oxidative modification.