▎ 摘　　要

Cytochrome c (Cyt c) and horseradish peroxidase (HRP) were co-immobilized on graphene oxide (GO)-chitosan (CHIT) modified Au electrode and the electron-transfer between the two proteins was investigated. The GO-CHIT nanocomposite was assembled on an Au electrode which covered by a mixed self-assembled monolayer of mecraptoundecanoic acid (MUA) and 6-mercapto-1-hexanol (MCH) and coated with Cyt c. The GO-CHIT nanocomposite as a novel electrochemical platform designed by combining the biocompatibility of CHIT and the conductivity of GO was used for the immobilization of the redox enzymes. Based on electrostatic interactions, the Cyt c-HRP/GO-CHIT/Cyt c/MUA-MCH/Au electrode was constructed by a layer-by-layer technique. Electron transfer and electrocatalytic performances of the modified electrode were investigated. Results showed that direct electron transfer has been established for the bi-protein system and the average rate constant of electron transfer k(s), ((Cyt c - HRP)) = 2.63 s(-1) was larger than those values at the electrodes modified with single protein (k(s, (Cyt c)) = 1.44 s(-1), k(s, (HRP)) = 1.53 s(-1)). The bi-protein modified electrode exhibited good electrocatalytic response to reduction of oxygen (O(2)) and hydrogen peroxide (H(2)O(2)), suggesting that a third-generation biosensor could be obtained for the detection of O(2) and H(2)O(2).