The electrochemistry of ubiquinone-10 in a phospholipid model membrane

The electrochemistry of ubiquinone-10, UQ, incorporated over a phospholipid layer adsorbed on a mercury drop electrode has been investigated over a wide pH range. It is shown that the position of the quinone headgroup in relation to the lipid determines the reversibility of the redox chemistry. For...

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Autores principales: Gordillo, G.J., Schiffrin, D.J.
Formato: JOUR
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pH
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_13596640_v116_n_p89_Gordillo
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Sumario:The electrochemistry of ubiquinone-10, UQ, incorporated over a phospholipid layer adsorbed on a mercury drop electrode has been investigated over a wide pH range. It is shown that the position of the quinone headgroup in relation to the lipid determines the reversibility of the redox chemistry. For pH < 7, the reaction follows a disproportionation route involving the ubiquinone radical. There is evidence for the presence of a parallel reaction sequence. The bifurcation point appears to occur for the UQ molecule, which disproportionates after protonation and reduction, in parallel with direct electron transfer to yield the UQ:- radical anion. The incorporation of UQ in a lipid monolayer makes its reduction very irreversible for pH > 7.