ORCID Profile
0000-0001-5855-651X
Current Organisations
HydRegen Limited
,
University of Oxford
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Publisher: Wiley
Date: 12-06-2020
Publisher: American Chemical Society (ACS)
Date: 12-04-2019
DOI: 10.26434/CHEMRXIV.7982864.V1
Abstract: Chemicals labelled with the heavy hydrogen isotope deuterium ( 2 H) have long been used in chemical and biochemical mechanistic studies, spectroscopy, and as analytical tracers. More recently, demonstration of selectively deuterated drug candidates that exhibit advantageous pharmacological traits has spurred innovations in metal-catalysed 2 H insertion at targeted sites, but asymmetric deuteration remains a key challenge. Here we demonstrate an easy-to-implement biocatalytic deuteration strategy, achieving high chemo-, enantio- and isotopic selectivity, requiring only 2 H 2 O (D 2 O) and unlabelled dihydrogen under ambient conditions. The vast library of enzymes established for NADH-dependent C=O, C=C, and C=N bond reductions have yet to appear in the toolbox of commonly employed 2 H-labelling techniques due to requirements for suitable deuterated reducing equivalents. By facilitating transfer of deuterium atoms from 2 H 2 O solvent to NAD + , with H 2 gas as a clean reductant, we open up biocatalysis for asymmetric reductive deuteration as part of a synthetic pathway or in late stage functionalisation. We demonstrate enantioselective deuteration via ketone and alkene reductions and reductive amination, as well as exquisite chemo-control for deuteration of compounds with multiple unsaturated sites.
Publisher: Wiley
Date: 11-05-2021
Abstract: A new activity for the [NiFe] uptake hydrogenase 1 of Escherichia coli (Hyd1) is presented. Direct reduction of biological flavin cofactors FMN and FAD is achieved using H 2 as a simple, completely atom‐economical reductant. The robust nature of Hyd1 is exploited for flavin reduction across a broad range of temperatures (25–70 °C) and extended reaction times. The utility of this system as a simple, easy to implement FMNH 2 or FADH 2 regenerating system is then demonstrated by supplying reduced flavin to Old Yellow Enzyme “ene‐reductases” to support asymmetric alkene reductions with up to 100 % conversion. Hyd1 turnover frequencies up to 20.4 min −1 and total turnover numbers up to 20 200 were recorded during flavin recycling.
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C004274A
Abstract: Direct electrochemical methods have been productive in revealing mechanistic details of catalysis by a range of metalloenzymes including hydrogenases and carbon and nitrogen cycling enzymes. In this approach, termed protein film electrochemistry, the protein is attached or adsorbed on the electrode surface and exchanges electrons directly, providing precise control over redox states or catalysis and avoiding diffusion-limited electron transfer. The 'edge' surface of pyrolytic graphite has proved to be a particularly good surface for adsorption of proteins in electroactive conformations. We now describe development of an approach that combines the precise control achieved in direct electrochemical measurements at a graphite electrode with surface infrared (IR) spectroscopic analysis of chemistry occurring at metallocentres in proteins. Hydrogenases are of particular interest: their unusual organo-metallic active sites--iron or nickel-iron centres coordinated by CO and CN(-)--give rise to IR v(CO) and v(CN) bands that are detected readily because these ligands are strong vibrational oscillators and are sensitive to changes in electron density and coordination at the metals. Small diatomic species also bind as exogenous ligands (as substrate, product, activator or inhibitor) to a range of other important metalloproteins, and understanding their reactivity and binding selectivity is critical in building up a multidimensional picture of enzyme chemistry and evolutionary history. The surface IR spectroelectrochemical approach we describe is based around Attenuated Total Reflectance (ATR) mode s ling of a film of pyrolytic graphite particles modified with a protein of interest. The particle network extends the electrode into three-dimensional space, providing sufficient adsorbed protein for spectroscopic analysis under precise electrochemical control. This strategy should open up new opportunities for detection of redox-dependent chemistry at metal centres in proteins, including short-lived catalytic intermediates and time-resolved details of catalysis and inhibition.
Publisher: Wiley
Date: 28-10-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2CC02411J
Abstract: Soluble hydrogenase enables atom efficient, H 2 -driven, recycling of synthetic nicotinamide cofactors.
Publisher: Portland Press Ltd.
Date: 06-01-2017
DOI: 10.1042/BCJ20160513
Abstract: The present study considers the ways in which redox enzyme modules are coupled in living cells for linking reductive and oxidative half-reactions, and then reviews ex les in which this concept can be exploited technologically in applications of coupled enzyme pairs. We discuss many ex les in which enzymes are interfaced with electronically conductive particles to build up heterogeneous catalytic systems in an approach which could be termed synthetic biochemistry. We focus on reactions involving the H+/H2 redox couple catalysed by NiFe hydrogenase moieties in conjunction with other biocatalysed reactions to assemble systems directed towards synthesis of specialised chemicals, chemical building blocks or bio-derived fuel molecules. We review our work in which this approach is applied in designing enzyme-modified particles for H2-driven recycling of the nicotinamide cofactor NADH to provide a clean cofactor source for applications of NADH-dependent enzymes in chemical synthesis, presenting a combination of published and new work on these systems. We also consider related photobiocatalytic approaches for light-driven production of chemicals or H2 as a fuel. We emphasise the techniques available for understanding detailed catalytic properties of the enzymes responsible for in idual redox half-reactions, and the importance of a fundamental understanding of the enzyme characteristics in enabling effective applications of redox biocatalysis.
Publisher: Wiley
Date: 10-08-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3SC01718D
Publisher: American Chemical Society (ACS)
Date: 31-01-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7CC02591B
Abstract: We manipulate and verify the redox state of single metalloprotein crystals by combining electrochemical control with synchrotron infrared microspectroscopy.
Publisher: Elsevier BV
Date: 12-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1SC00295C
Abstract: Heterogeneous chemo-bio catalytic hydrogenation is an attractive strategy for clean, enantioselective CX reduction.
Publisher: American Chemical Society (ACS)
Date: 15-06-2016
Publisher: Springer Science and Business Media LLC
Date: 19-03-2020
DOI: 10.1038/S41467-020-15310-Z
Abstract: Enzymes dependent on nicotinamide cofactors are important components of the expanding range of asymmetric synthetic techniques. New challenges in asymmetric catalysis are arising in the field of deuterium labelling, where compounds bearing deuterium ( 2 H) atoms at chiral centres are becoming increasingly desirable targets for pharmaceutical and analytical chemists. However, utilisation of NADH-dependent enzymes for 2 H-labelling is not straightforward, owing to difficulties in supplying a suitably isotopically-labelled cofactor ([4- 2 H]-NADH). Here we report on a strategy that combines a clean reductant (H 2 ) with a cheap source of 2 H-atoms ( 2 H 2 O) to generate and recycle [4- 2 H]-NADH. By coupling [4- 2 H]-NADH-recycling to an array of C=O, C=N, and C=C bond reductases, we demonstrate asymmetric deuteration across a range of organic molecules under ambient conditions with near-perfect chemo-, stereo- and isotopic selectivity. We demonstrate the synthetic utility of the system by applying it in the isolation of the heavy drug (1 S ,3’ R )-[2’,2’,3’- 2 H 3 ]-solifenacin fumarate on a preparative scale.
Publisher: Wiley
Date: 26-01-2021
DOI: 10.1002/JLCR.3899
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7CC04465H
Abstract: We describe the implementation of a system of immobilised enzymes for H 2 -driven NADH recycling coupled to a selective biotransformation to enable H 2 -driven biocatalysis in flow.
Publisher: Wiley
Date: 11-05-2021
Abstract: A new activity for the [NiFe] uptake hydrogenase 1 of Escherichia coli (Hyd1) is presented. Direct reduction of biological flavin cofactors FMN and FAD is achieved using H 2 as a simple, completely atom‐economical reductant. The robust nature of Hyd1 is exploited for flavin reduction across a broad range of temperatures (25–70 °C) and extended reaction times. The utility of this system as a simple, easy to implement FMNH 2 or FADH 2 regenerating system is then demonstrated by supplying reduced flavin to Old Yellow Enzyme “ene‐reductases” to support asymmetric alkene reductions with up to 100 % conversion. Hyd1 turnover frequencies up to 20.4 min −1 and total turnover numbers up to 20 200 were recorded during flavin recycling.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1CC14826E
Abstract: Pyrolytic graphite particles modified with hydrogenase and an NAD(+)/NADH cycling enzyme provide a modular heterogeneous catalyst system for regeneration of oxidised or reduced nicotinamide cofactors using H(2) and H(+) as electron source or sink. Particles can be tuned for cofactor supply under different conditions by appropriate choice of hydrogenase.
Publisher: American Chemical Society (ACS)
Date: 11-02-2021
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Holly Reeve.