Acta Phys. -Chim. Sin. ›› 2007, Vol. 23 ›› Issue (01): 5-11.doi: 10.1016/S1872-1508(07)60002-3

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Direct Electrochemistry and Bioelectrocatalysis of Myoglobin at a Carbon Nanotube-Modified Electrode

LÜ Ya-Fen;YIN Ya-Jing;WU Ping;CAI Chen-Xin   

  1. Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Chemistry and Environmental Science, Nanjing Normal University, Nanjing 210097, P. R. China
  • Received:2006-06-06 Revised:2006-08-02 Published:2007-01-08
  • Contact: CAI Chen-Xin E-mail:cxcai@njnu.edu.cn

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Abstract: Myoglobin (Mb) was immobilized onto the surface of carbon nanotube (CNT) and was characterized by AFM, XPS, UV-Vis, and FTIR spectroscopy. The promotion effect of CNT on direct electron transfer (DET) reaction of Mb was studied. Cyclic voltammetric results showed a pair of well-defined redox peaks, which corresponded to DET of Mb, with the formal potential (E0′) of (−0.343±0.001) V (vs SCE) in the phosphate buffer solution (PBS, pH 7.0). The electrochemical parameters, such as apparent heterogeneous electron transfer rate constant (ks) and E0′, were determined. The dependence of E0′ on solution pH indicated that DET reaction of Mb was coupled with proton transfer. The experimental results also demonstrated that the immobilized Mb retained its bioelectrocatalytic activity toward the reduction of H2O2 and O2.

Key words: Bioelectrocatalysis, Direct electron transfer, Carbon nanotube, Hydrogen peroxide, Myoglobin