Electron transfer and electrocatalytics of cytochrome c and horseradish peroxidase on DNA modified electrode.

A bio-interphase composed of DNA, cytochrome c (Cyt c) and horseradish peroxidase (HRP) was developed by layer-by-layer assembling Cyt c, DNA and Cyt c-HRP on biocompatible 11-mercaptoundecanoic acid--6-mercapto-1-hexanol modified gold electrode. The new bio-interphase was used as a model system to mimic the electron transfer and electrocatalytic performance of two proteins in living organisms. Results showed that the electron transfer rate at bi-protein bio-interphase was faster than those at the single protein bio-interphase, indicating a synergistic interaction between the two proteins occurred in the electron transfer. Moreover, the mixed proteins modified electrode exhibited good electrocatalytic response to reduction of hydrogen peroxide (H₂O₂) and oxygen (O₂), suggesting that it could be used as a sensor for H₂O₂ and O₂ detection. The properties of the bio-interphase, together with the bioelectrocatalytic activity, could make it useful in the development of bioelectronic devices, and investigation of electrochemistry of other heme proteins at functional interphase. It would also provide a new strategy for further study on the electron transfer of other multi-proteins in a bio-interphase and the development of biosensors.