Molecular mechanism of composite nanoparticles TiO2/WO3/GO-induced activity changes of catalase and superoxide dismutase

More and more composite nano-photocatalysts were developed by doping, modifying and coupling, which expanded its application but resulted in pollution due to the unrecyclability. Composite photocatalyst TiO2/WO3/GO, as a model, was evaluated by exploring the molecular mechanism of TiO2/WO3/GO-induced activity changes of catalase (CAT) and superoxide dismutase (SOD). Results showed that TiO2/WO3/GO could lead to conformational and functional changes of CAT and SOD. The activity of both CAT and SOD increased depending on the exposure dose of TiO2/WO3/GO. The change skeleton structure and increase of a-helix content of CAT and SOD were certificated with UV-vis absorption and CD measurements. Intrinsic fluorescence of CAT and SOD were quenched by dynamic quenching. Micro-environment of amino acid residues of CAT and SOD became more hydrophilic, and the microenvironment of Trp residues was more vulnerable than Tyr residues with TiO2/WO3/GO exposure. In addition, inhibitory comparison between GO, TiO2 , WO3 and TiO2/WO3/GO was made, results showed that composite nano-photocatalyst exhibited different inhibitory compared to their parent nano-particles.