Electrochemical studies of single-wall carbon nanotubes as nanometer-sized activators in enzyme-catalyzed reaction

• Published in: Analytica chimica acta Vol. 511; no. 2; pp. 239 - 247
• Main Authors: Gan, Zhen-Hai, Zhao, Qiang, Gu, Zhen-Nan, Zhuang, Qian-Kun
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.05.2004; Elsevier
• Subjects: Analytical chemistry; atomic force microscopy; Carbon; Carbon nanotubes; Chemistry; Chronoamperometry; Electrochemical methods; Electrodes; Enzymes; Exact sciences and technology; Guanylate cyclase; L-Lactate dehydrogenase; Lactate dehydrogenase; Lanthanum; Lanthanum ion; nanotubes; Nicotine; Oxalic acid; Q1; Spectrometric and optical methods; SWNT-modified electrode; Carbon nanotubes; Lactate dehydrogenase; Chronoamperometry; SWNT-modified electrode; Lanthanum ion; Atomic force microscopy; Catalytic reaction; Chemical analysis; Enzyme; Electrochemical method; Carbon electrode; Reaction rate; L-Lactate dehydrogenase; Cyclic voltammetry; Enzymatic activity; Oxalic acid; Michaelis constant; Raman spectrometry; Oxidoreductases; Inhibition; Lanthanum; Nicotine
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2004.01.055

Chronoamperometry based on the “controlling-diffusion layer” concept of the convective system was used to assay the activity of lactate dehydrogenase (LDH) on a bare glassy carbon (GC) electrode and a GC electrode modified by a single-wall carbon nanotube (SWNT) film. The effects of lanthanum ion, oxalic acid, and nicotine on the LDH activity were monitored. Analysis of the experimental results revealed that the single-wall carbon nanotubes could markedly increase the activity of LDH. The activation and inhibition were characterized by three quantities: the real initial reaction rate ( V 0) and the maximum reaction rate ( V max) of the enzyme-catalyzed reaction and the Michaelis–Menten constant ( K m). Tapping mode atomic force microscopy (AFM) images and the Raman spectra unambiguously demonstrated that the single-wall carbon nanotubes could interact with the enzyme LDH while the SWNT-modified electrode was under the potential control. In this case, the activation of SWNT was attributed to the interaction of SWNTs with the enzyme.