The electrochemical properties of thermophilic cytochrome P450 CYP119A2 at extremely high temperatures in poly(ethylene oxide)

The electrochemical measurements were carried out by using thermophilic cytochrome P450 CYP119A2 (P450st) modified with poly(ethylene oxide) (PEO) in PEO200 as an electrochemical solvent. The PEO modified P450st gave clear reduction–oxidation peaks by cyclic voltammetry in oxygen-free PEO200 up to 120 °C. The midpoint potential measured for the P450st was −120 mV vs. [Fe(CN)6]4−/[Fe(CN)6]3− at 120 °C. The peak separation, ΔE, was 16 mV at 100 mV/s. The estimated electron transfer rate of PEO-P450st at 120 °C was 35.1 s−1. The faster electron transfer reaction was achieved at higher temperatures. The electrochemical reduction of dioxygen was observed at 115 °C with the PEO-modified P450st system.