Event date:
Feb 15 2022 7:00 pm

CCEW-10: The Importance of Enzymes, Electrons and Nanospace for the Future of Catalysis

Fraser Armstrong from St John’s College and Department of Chemistry, University of Oxford
Using a suite of techniques known as Protein Film Electrochemistry, the chemical reactivity and catalytic action of many enzymes have been revealed in exquisite detail, leading to the detection of previously hidden properties and insight into how such catalysts must have evolved. Physical scientists are well aware of the unique ability of the platinum metals for activating hydrogen: indeed, until recently the reversible hydrogen electrode comprised of Pt was the only example of a reversible electrocatalyst, one in which the current (proportional to reaction rate) switches direction abruptly at the reversible potential. In the past 20 years, it has become clear that when attached to an electrode, hydrogenases, electron-transferring enzymes produced by microbes, are also reversible electrocatalysts – a mark of extreme efficiency that is not only important in technology but essential for living cells that must make best use of every Joule. Significantly, we now know that this special property is widespread among other enzymes, those responsible for CO2 activation as well as ones catalyzing a host of other reactions of interest for renewable energy and (very importantly) for which we have detailed structural information. Although direct application of electron-transferring enzymes in energy technology is limited by their size, stability and cost – they are truly inspirational. Looking beyond single catalysts, we look to nanoconfinement. Trapped in the nanopores of an electrode formed from indium tin oxide nanoparticles, a small photosynthetic enzyme known as FNR uses electrons to recycle local NADP(H) reversibly and at great speed: this action is used to energize and observe other trapped enzymes that include at least one dehydrogenase, thus allowing us to drive extended cascades where intermediates are prevented from escaping. Nanoconfinement is a characteristic of living cells: mimicking it by using electronically conducting nanomaterials leads to a powerful new way to energize, observe, and exploit the properties of myriad existing and yet-to-emerge enzymes, promoting a fresh era of discovery.

Fraser Armstrong is Emeritus Professor of Chemistry and a Fellow of St John’s College. His interests are in biological chemistry, bioenergetics and in the mechanisms and exploitation of enzymes related to energy production.

He has received a number of awards including the European Award for Biological Inorganic Chemistry, the Carbon Trust Innovation Award, the Max Planck Award for Frontiers in Biological Chemistry and the Royal Society of Chemistry Award for Interdisciplinary Chemistry.

He travels widely giving invited lectures on topics including catalysis, bioenergetics and renewable energy. He is co-editor of Energy … beyond oil which focuses on alternative energy-generating technologies.

Fraser has been elected Fellow of the Royal Society.