Cytochrome c electrode

M.K. Beissenhirtz, F.W. Scheller, and F. Fisdat, A superoxide sensor based on a multilayer cytochrome c electrode. Anal. Chem. 76, 4665-4671 (2004). 

R.H. Fabian, D.S. DeWitt, and T.A. Kent, In vivo detection of superoxide anion production by the brain using a cytochrome c electrode. Cereh. Blood Flow Metah. 15, 242-247 (1995). 

Fig. 2.10. (a) Illustration of the reactions while measuring superoxide anion with a cytochrome c electrode and (b) Superoxide anion measurement. Cytochrome c was immobilized on MUA/MU-modified gold electrode. The working potential is + 130 mV. Superoxide was generated by XOD in buffer with 100 p.M h5TX)xeinthine. ((b) Reproduced from Ref. [143] with permission from Elsevier.)... 

Figure 5.14 Catalytic response of a multilayered human SO-cytochrome c electrode in 1 mM sulfite as a function of the number of protein layers (a) n = 2, (h) n = 4, (c) n = 6 and (d) n = 8. Sweep rate 100 mV s. (Inset) Electrode scheme red circles = cytochrome c and hlue objects = human SO. Reprinted with permission from ref. 93. Copyright 2008 American Chemical Society.

Armstrong FA, Bond AM, Buchi FN, Hanmett A, Hill HAO, Lannon AM, Lettington OC, Zoski CG. 1993. Electrocatalytic reduction of hydrogen-peroxide at a stationary pyrol3ftic-graphite electrode surface in the presence of cytochrome-c peroxidase— A description based on a microelectrode array model for adsorbed enzyme molecules. Analyst 118 973-978. 

Mayer D, Ataka K, Heberle J, Offenhaeusser A. 2005. Scanning probe microscopic studies of the oriented attachment and membrane reconstitution of cytochrome c oxidase to a gold electrode. Langmuir 21 8580-8583. 

A redox reaction is a special case of the equilibrium reaction of A + B in Equation 13.1 B is now a reducible group in a biomolecule with an EPR spectrum either in its oxidized or in its reduced state (or both), and A is now an electron or a pair of electrons, that is, reducing equivalents provided by a natural redox partner (a reductive substrate, a coenzyme such as NADH, a protein partner such as cytochrome c), or by a chemical reductant (dithionite), or even by a solid electrode ... 

Figure 3.89 Cyclic voltammograms of 500 pm cytochrome c at a gold electrode modified by (a) 2-mercaptopyridine, (b> 2-mercaptosuccinic acid, 4,4 -dithiobis(butanoic acid), (d) 4-mercaploaniline. pH 7.0 phosphate buffer +0.1 M NaC104. Scan rale 50mVs . From Allen...

The results clearly showed the importance of directionality. 4-lhiopyridine is an excellent promoter, while the 2 isomer shows no activity. After adsorption the 4 isomer has the pyridine nitrogen direction out into solution while the 2 isomer points the N back towards the electrode where it is available for adsorption to the gold rather than the cytochrome c. 

Figures 3.91(a) and (b) show cyclic voltammograms of the SERS electrode in aqueous solutions of the SSBipy and PySH. In the potential range —0.3 V to 0.3 V vs. SCE, which is the range of interest for the reversible reduction of cytochrome c, no notable faradaic currents were observed for either of these species. However, at potentials < —0.4 V SSBipy is reduced to PySH and the PySH so formed is re-oxidised to SSBipy at potentials >0.1 V. Similarly, PySH is oxidised to SSBipy at potentials >0.1 V and this product re-reduced at potentials < —0.4 V.

Figure 3.92 shows SERS spectra of adsorbed SSBipy and PySH at 0 V in the absence of the solution species, together with the Raman spectra of PySH in solution and crystalline SSBipy. The activities of the modified electrodes were first confirmed in solution containing cytochrome c. 

At this point it was clear how SSBipy was adsorbed on the electrode and the timescale over which this occurred, as well as the role of the concentration of the initial solution. However, the actual mode of action of the adsorbed species still remained somewhat obscure. An important insight into this was provided by the work of Hill et al. in 1987 who studied the effect of partial substitution of the layer of adsorbed promoter on the electrochemistry of cytochrome c. 

F. Lisdat, B. Ge, E. Ehrentreich-Forster, R. Reszka, and F.W. Scheller, Superoxide dismutase activity measurement using cytochrome c-modified electrode. Anal. Chem. 71,1359—1365 (1999). 

K. Tammeveski, T. Tenno, A.A. Mashirin, E.W. Hillhouse, P. Manning, and CJ. McNeil, Superoxide electrode based on covalently immobilized cytochrome c modeling studies. Free Radical Biol. Med. 25, 973-978 (1998). 

K.V. Gobi and F. Mizutani, Efficient mediatorless superoxide sensors using cytochrome c-modified electrodes. Surface nano-organization for selectivity and controlled peroxidase activity. J. Electroanal. Chem. 484, 172-181 (2000). 

J.C. Cooper, G. Thompson, and C.J. McNeil, Direct electron transfer between immobilized cytochrome c and gold electrodes. Mol. Cryst. Liq. Cryst. 235, 127-132(1993). 

K.D. Gleria, H.A.O. Hill, V.J. Lowe, and D.J. Page, Direct electrochemistry of horse-heart cytochrome c at amino acid-modified gold electrodes. J. Electroanal. Chem. 213, 333-338 (1986). 

J. Wang, M. Li, Z. Shi, N. Li, and Z. Gu, Direct electrochemistry of cytochrome c at a glassy carbon electrode modified with single-wall carbon nanotubes. Anal. Chem. 74, 1993-1997 (2002). 

G.C. Zhao, Z.Z. Yin, L. Zhang, and X.W. Wei, Direct electrochemistry of cytochrome c on a multi-walled carbon nanotube modified electrode and its electrocatalytic activity for the reduction of H2O2. Electrochem. Commun. 7, 256-260 (2005). 

The first reports on direct electrochemistry of a redox active protein were published in 1977 by Hill [49] and Kuwana [50], They independently reported that cytochrome c (cyt c) exhibited virtually reversible electrochemistry on gold and tin doped indium oxide (ITO) electrodes as revealed by cyclic voltammetry, respectively. Unlike using specific promoters to realize direct electrochemistry of protein in the earlier studies, recently a novel approach that only employed specific modifications of the electrode surface without promoters was developed. From then on, achieving reversible, direct electron transfer between redox proteins and electrodes without using any mediators and promoters had made great accomplishments. 

FIGURE 17.3 Scheme of the detection principle of antioxidant activity using a cytochrome c functionalized gold electrode. A0I is the antioxidant under investigation. (From [213], with permission.)... 

L. Wang and E.K. Wang, Direct electron transfer between cytochrome c and a gold nanoparticles modified electrode. Electrochem. Commun. 6, 49—54 (2004). 

D.E. Reed and F.M. Hawkridge, Direct electron transfer reactions of cytochrome c at silver electrodes. Anal. Chem. 59, 2334-2339 (1987). 

P. Yeh and T. Kuwana, Reversible electrode reaction of cytochrome c. Chem. Lett. 1145-1148 (1977). 

H. Allen, O. Hill, N.I. Hunt, and A.M. Bond, The transient nature of the diffusion controlled component of the electrochemistry of cytochrome c at bare gold electrodes an explanation based on a self-blocking mechanism. J. Electroanal. Chem. 436, 17-25 (1997). 

S.M. Chen and S.V. Chen, The bioelectrocatalytic properties of cytochrome c by direct electrochemistry on DNA film modified electrode. Electrochim. Acta 48, 513-529 (2003). 

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