Ubiquinol-cytochrome c reductase (Complex III) electrochemistry at multi-walled carbon nanotubes/Nafion modified glassy carbon electrodes

作者：Pelster Lindsey N; Minteer Shelley D^*

来源：Electrochimica Acta, 2012, 82: 214-217.

DOI：10.1016/j.electacta.2011.11.121

• Ubiquinol-cytochrome c reductase
• Electron transport chain
• Bioelectrocatalysis
• Cytochrome c

Electron transport chain complexes are critical to metabolism in living cells. Ubiquinol-cytochrome c reductase (Complex III) is responsible for carrying electrons from ubiquinol to cytochrome c, but the complex has not been evaluated electrochemically. This work details the bioelectrochemistry of ubiquinol-cytochrome c reductase of the electron transport chain of tuber mitochondria. The characterization of the electrochemistry of this enzyme is investigated in carboxylated multi-walled carbon nanotube/tetrabutyl ammonium bromide-modified Nafion (R) modified glassy carbon electrodes by cyclic voltammetry. Increasing concentrations of cytochrome c result in a catalytic response from the active enzyme in the nanotube sandwich. The experiments show that the enzyme followed Michaelis-Menten kinetics with a K-m for the immobilized enzyme of 2.97 (+/-0.11) x 10(-6) M and a V-max of 6.31 (+/-0.82) x 10(-3) mu mol min(-1) at the electrode, but the Km and Vmax values decreased compared to the free enzyme in solution, which is expected for immobilized redox proteins. This is the first evidence of ubiquinol-cytochrome c reductase bioelectrocatalysis.

• 出版日期2012-11-1