A nano self-assembled artificial peroxidase: spectroscopic and electrochemical investigations

A nano-micelle with highly efficient peroxide activity was constructed by self-assembly of sodium dodecyl sulfate micellar, histidine and hematin in 50 mM phosphate buffer at 25 °C. UV–Vis spectrometry methods were utilized for characterization of the nanostructured material or artificial peroxidase (AP). The Michaelis–Menten (K _m) and catalytic rate (k _cat) constants of the AP were obtained to be 5.5 μM and 0.06 s^?1, respectively, in 50 mM phosphate buffer solution at pH 8.0. The catalytic efficiency of AP was evaluated to be 0.011 μM^?1 s^?1. The AP was also immobilized on a functional multi-wall carbon nanotubes-gold nanoparticles (AuNPs) nano-complex modified glassy carbon electrode (GCE). The transmission electron microscopy method was utilized for the characterization of the nano-materials. The electron-transfer rate constant (k _s) and the apparent Michaelis–Menten constant K _m ^app of the AP modified GCE were evaluated to be 1.36 s^?1 and 0.19 μM, respectively. For a biosensor without a redox protein, the properties of the AP modified GCE were significant and will further benefit from additional studies and improvement.