Interface properties of cytochrome c on a nano-textured diamond surface

The electron transfer process and the peroxidase activity of native and denatured cytochrome c were investigated on OH-terminated diamond nano-textured surfaces. The nano-textured surfaces with geometrical properties of typical protein dimensions were fabricated by a top-down technology, where diamond nanoparticles are used as etching masks. The cyclic voltammogram of native cytochrome c shows an adsorption-controlled, reversible electron transfer process of the heme redox center, which was not detected for denatured cytochrome c. Native cytochrome c denatures in the presence of hydrogen peroxide. Higher peroxidase activity was found on the denatured cytochrome c than on native cytochrome c. The apparent Michaelis–Menten constants Km for denatured cytochrome c and the native cytochrome c were determined to be 0.08 and 0.23 mM, respectively.

Research Highlights
► Cytochrome c was three-dimensionally entrapped on nano-textured diamond surface.
► Direct electron transfer of cytochrome c was realized on diamond nano-textures.
► Higher peroxidase activity was found for denatured cytochrome c than native one.