Collect. Czech. Chem. Commun. 2005, 70, 305-312

Investigations on the Reduction of Molecular Oxygen on Polyphenol Oxidase-Modified Electrode

Hui Jiang, Chun-Hua Shi, Yong-Shu Xie and Qing-Liang Liu*

Department of Chemistry, University of Science and Technology of China, Hefei, 230026, P. R. China


Polyphenol oxidase (PPO, E.C. from Nicotiana tobacum, PPO II, shows a different behavior from that of PPOs from other sources. A one-electron oxygen reduction on PPO II - Nafion modified glassy carbon electrode surface has been observed by square-wave voltammetry. The cathodic peak has been found to be proportional to the concentration of dissolved oxygen. The optimum salt concentration was 0.2 mol/l. The study of its dependence on pH (4-9) indicates that the reduction of oxygen is accompanied by a one-proton-transfer process. Temperature shows little influence on the cathodic peak. The electrode storage has also been studied to evaluate its stability.

Keywords: Square-wave voltammetry; Polyphenol oxidase; Oxygen detection; Nafion modified electrode; Enzymes; Modified electrodes; Electrochemistry.

References: 30 live references.