Direct Electrochemistry of Artificial Peroxidase Based on Self-Assembled Cytochrome c-SDS-Nano-Micelle

摘要

A peroxidase activity nano-artificial enzyme (AP) was designed by feeding cytochrome c (Cty c) in sodium dodecyl sulfate (SDS) nano-micelle in 50 mM, pH 10.5 sodium phosphate buffer solution (PBS), and 30% catalytic efficiency of native HRP was achieved. The UV-Vis, Circular Dichroism (CD) specropolarimetry, Surface Tension and Isothermal titration calorimetric (ITC) methods were utilized for additional characterization of the AP. Direct electron transfer between AP and electrode was achieved by immobilizing the monolayer of AP on a glassy carbon electrode using the electro-deposition method. CMCs of Cyt-SDS micelle and SDS micelle were determined to be 4.68 mM and 4.83 mM, respectively, in 50 mM PBS at pH 10.5. The aggregation number of SDS in Cyt c-SDS-nano-micelle was calculated to be 116. The immobilized AP modified electrodes showed quasi-reversible electrochemical redox behaviors with a formal potential of -38 ± 5 mV (vs. Ag/AgCl) at a scan rate of 50 mV/s. The cathodic transfer coefficient and electron transfer rate constant were evaluated to be 0.51 and 0.72 s ~(-1), respectively. The apparent Michaelis-Menten constant was calculated to be 0.14 mM.