The Vincent group is based in the #Chemistry Department at the University of Oxford, UK. We are a primarily a bio-inorganic research group, with an interest in small molecular activation at metal centres in #enzymes. We have worked on #hydrogenase enzymes for several decades. These enzymes are inspirational to chemists because they use a catalytic site built from earth-abundant metals - nickel and/or iron - to activate hydrogen gas. In contrast, chemists still rely heavily on precious metals such as platinum or palladium for activating hydrogen. The Vincent group have developed a range of tools for studying the mechanism of the highly active #hydrogenase enzymes by coupling #electrochemistry with spectroscopy. We make extensive use of infrared spectroscopy, which reports on the vibrational changes at CO and CN- ligands at the active site of hydrogenases, while using electrochemistry to switch on/off #catalysis during measurements.
More recently, we have demonstrated #electrochemical control over single crystals of hydrogenase, allowing us to collect X-ray diffraction structures in well-defined redox states relevant to the catalytic cycle. This makes important links between observations made on solution samples and crystals of these enzymes. We have built up a significant structural biology sub-group, and are extending these approaches to other #metalloenzymes with roles in small #molecule activation, such as nitrogenase.
Our work on hydrogenases led us into biotechnology about 12 years ago. In particular, we became interested in more #sustainable ways of driving biocatalysis, replacing carbon-based reductants with hydrogen gas. We have developed #hydrogen-driven systems for recycling the reduced cofactors NADH and NADPH and flavins for application in biotechnology, and more recently we have developed a biocatalytic system for hydrogen-driven reduction of nitro-group to amines. We are also developing methods for reductant supply to dioxygen-dependent enzymes using safe mixtures of dihydrogen/dilute dioxygen. A key motivation for us is to make #bicoatalysis easier to operate, more atom-efficient, and more sustainable.
Our catalyst developments for #biotechnology are informed by our use of electrochemistry: we study enzyme #redox reactions as separate half reactions at an electrode, for example, the oxidation of dihydrogen, or the reduction of NAD+, allowing us to combine components in unique ways on electrically-conductive supports. We take inspiration from the model of ‘mixed potential theory’ discussed in heterogeneous catalysis. Our favourite support material is #carbon black, since it is already well-established as an industrial catalyst support and allows facile immobilisation of enzymes by direct adsorption. Since the enzymes are immobilised on carbon particles, these heterogeneous biocatalyst systems are ideal for translation into continuous flow, and we have applied #biocatalytic hydrogenations in continuous flow.
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