Issue 24, 2024

Re-assessing viologens for modern bio-electrocatalysis


Viologens, 1,1′-disubstituted-4,4′-bipyridinium salts, are organic redox species that can be used in place of NADPH as mediators for redox enzymes. In this study, using the reduction of oxidized glutathione by glutathione reductase as a model system, a rationally designed library of viologens covering a range of polarities and functional groups were explored as electron transfer mediators for bio-electrocatalysis. Through a series of electrochemical investigations, the reduction potential was found to be the primary determining factor for electron transfer between the viologen and enzyme. Through enhancing the solubility of viologen such that the fully reduced state remained soluble, we demonstrate a much-widened window of useable viologen potentials. In doing so, we describe for the first time a highly efficient electron transfer to a flavoenzyme promoting the catalytic reaction in the absence of co-factors. As such, our study provides a platform for broadening the scope for using viologens as mediating agents for electrochemically-driven enzymatic processes.

Graphical abstract: Re-assessing viologens for modern bio-electrocatalysis

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Article information

Article type
Edge Article
12 Apr 2024
16 May 2024
First published
16 May 2024
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2024,15, 9325-9332

Re-assessing viologens for modern bio-electrocatalysis

D. A. Koomson, J. H. Nicholson, A. P. S. Brogan and L. Aldous, Chem. Sci., 2024, 15, 9325 DOI: 10.1039/D4SC02431A

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