1
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Mazzarella D, Qi C, Vanzella M, Sartorel A, Pelosi G, Dell'Amico L. Electrochemical Asymmetric Radical Functionalization of Aldehydes Enabled by a Redox Shuttle. Angew Chem Int Ed Engl 2024; 63:e202401361. [PMID: 38623693 DOI: 10.1002/anie.202401361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 04/08/2024] [Accepted: 04/14/2024] [Indexed: 04/17/2024]
Abstract
Aminocatalysis is a well-established tool that enables the production of enantioenriched compounds under mild conditions. Its versatility is underscored by its seamless integration with various synthetic approaches. While the combination of aminocatalysis with metal catalysis, photochemistry, and stoichiometric oxidants has been extensively explored, its synergy with electrochemical activation remains largely unexplored. Herein, we present the successful merger of electrochemistry and aminocatalysis to perform SOMO-type transformations, expanding the toolkit for asymmetric electrochemical synthesis. The methodology harnesses electricity to drive the oxidation of catalytically generated enamines, which ultimately partake in enantioselective radical processes, leading to α-alkylated aldehydes. Crucially, mechanistic studies highlight how this electrochemical strategy is enabled by the use of a redox shuttle, 4,4'-dimethoxybiphenyl, to prevent catalyst degradation and furnishing the coveted compounds in good yield and high enantioselectivity.
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Affiliation(s)
- Daniele Mazzarella
- Department of Chemical Sciences, University of Padova, Via Francesco Marzolo 1, 35131, Padova, Italy
| | - Chun Qi
- Department of Chemical Sciences, University of Padova, Via Francesco Marzolo 1, 35131, Padova, Italy
| | - Michael Vanzella
- Department of Chemical Sciences, University of Padova, Via Francesco Marzolo 1, 35131, Padova, Italy
| | - Andrea Sartorel
- Department of Chemical Sciences, University of Padova, Via Francesco Marzolo 1, 35131, Padova, Italy
| | - Giorgio Pelosi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 17, 43124, Parma, Italy
| | - Luca Dell'Amico
- Department of Chemical Sciences, University of Padova, Via Francesco Marzolo 1, 35131, Padova, Italy
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2
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Kalimuthu P, Hakopian S, Niks D, Hille R, Bernhardt PV. The Reversible Electrochemical Interconversion of Formate and CO 2 by Formate Dehydrogenase from Cupriavidus necator. J Phys Chem B 2023; 127:8382-8392. [PMID: 37728992 DOI: 10.1021/acs.jpcb.3c04652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
The bacterial molybdenum (Mo)-containing formate dehydrogenase (FdsDABG) from Cupriavidus necator is a soluble NAD+-dependent enzyme belonging to the DMSO reductase family. The holoenzyme is complex and possesses nine redox-active cofactors including a bis(molybdopterin guanine dinucleotide) (bis-MGD) active site, seven iron-sulfur clusters, and 1 equiv of flavin mononucleotide (FMN). FdsDABG catalyzes the two-electron oxidation of HCOO- (formate) to CO2 and reversibly reduces CO2 to HCOO- under physiological conditions close to its thermodynamic redox potential. Here we develop an electrocatalytically active formate oxidation/CO2 reduction system by immobilizing FdsDABG on a glassy carbon electrode in the presence of coadsorbents such as chitosan and glutaraldehyde. The reversible enzymatic interconversion between HCOO- and CO2 by FdsDABG has been realized with cyclic voltammetry using a range of artificial electron transfer mediators, with methylene blue (MB) and phenazine methosulfate (PMS) being particularly effective as electron acceptors for FdsDABG in formate oxidation. Methyl viologen (MV) acts as both an electron acceptor (MV2+) in formate oxidation and an electron donor (MV+•) for CO2 reduction. The catalytic voltammetry was reproduced by electrochemical simulation across a range of sweep rates and concentrations of formate and mediators to provide new insights into the kinetics of the FdsDABG catalytic mechanism.
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Affiliation(s)
- Palraj Kalimuthu
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Sheron Hakopian
- Department of Biochemistry, University of California Riverside, 900 University Avenue, Riverside, California 92521, United States
| | - Dimitri Niks
- Department of Biochemistry, University of California Riverside, 900 University Avenue, Riverside, California 92521, United States
| | - Russ Hille
- Department of Biochemistry, University of California Riverside, 900 University Avenue, Riverside, California 92521, United States
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
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3
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Kalimuthu P, Harmer JR, Baldauf M, Hassan AH, Kruse T, Bernhardt PV. Catalytic electrochemistry of the bacterial Molybdoenzyme YcbX. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148579. [PMID: 35640667 DOI: 10.1016/j.bbabio.2022.148579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 05/02/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
Molybdenum-dependent enzymes that can reduce N-hydroxylated substrates (e.g. N-hydroxyl-purines, amidoximes) are found in bacteria, plants and vertebrates. They are involved in the conversion of a wide range of N-hydroxylated organic compounds into their corresponding amines, and utilize various redox proteins (cytochrome b5, cyt b5 reductase, flavin reductase) to deliver reducing equivalents to the catalytic centre. Here we present catalytic electrochemistry of the bacterial enzyme YcbX from Escherichia coli utilizing the synthetic electron transfer mediator methyl viologen (MV2+). The electrochemically reduced form (MV+.) acts as an effective electron donor for YcbX. To immobilize YcbX on a glassy carbon electrode, a facile protein crosslinking approach was used with the crosslinker glutaraldehyde (GTA). The YcbX-modified electrode showed a catalytic response for the reduction of a broad range of N-hydroxylated substrates. The catalytic activity of YcbX was examined at different pH values exhibiting an optimum at pH 7.5 and a bell-shaped pH profile with deactivation through deprotonation (pKa1 9.1) or protonation (pKa2 6.1). Electrochemical simulation was employed to obtain new biochemical data for YcbX, in its reaction with methyl viologen and the organic substrates 6-N-hydroxylaminopurine (6-HAP) and benzamidoxime (BA).
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Affiliation(s)
- Palraj Kalimuthu
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
| | - Jeffrey R Harmer
- Centre for Advanced Imaging, University of Queensland, Brisbane 4072, Australia
| | - Milena Baldauf
- Department of Plant Biology, Technische Universitaet, Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Ahmed H Hassan
- Department of Plant Biology, Technische Universitaet, Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Tobias Kruse
- Department of Plant Biology, Technische Universitaet, Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia.
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Kalimuthu P, Harmer JR, Baldauf M, Hassan AH, Kruse T, Bernhardt PV. Electrochemically driven catalysis of the bacterial molybdenum enzyme YiiM. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148523. [PMID: 34921810 DOI: 10.1016/j.bbabio.2021.148523] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/18/2021] [Accepted: 12/07/2021] [Indexed: 12/20/2022]
Abstract
The Mo-dependent enzyme YiiM enzyme from Escherichia coli is a member of the sulfite oxidase family and shares many similarities with the well-studied human mitochondrial amidoxime reducing component (mARC). We have investigated YiiM catalysis using electrochemical and spectroscopic methods. EPR monitored redox potentiometry found the active site redox potentials to be MoVI/V -0.02 V and MoV/IV -0.12 V vs NHE at pH 7.2. In the presence of methyl viologen as an electrochemically reduced electron donor, YiiM catalysis was studied with a range of potential substrates. YiiM preferentially reduces N-hydroxylated compounds such as hydroxylamines, amidoximes, N-hydroxypurines and N-hydroxyureas but shows little or no activity against amine-oxides or sulfoxides. The pH optimum for catalysis was 7.1 and a bell-shaped pH profile was found with pKa values of 6.2 and 8.1 either side of this optimum that are associated with protonation/deprotonations that modulate activity. Simulation of the experimental voltammetry elucidated kinetic parameters associated with YiiM catalysis with the substrates 6-hydroxyaminopurine and benzamidoxime.
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Affiliation(s)
- Palraj Kalimuthu
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
| | - Jeffrey R Harmer
- Centre for Advanced Imaging, University of Queensland, Brisbane, 4072, Australia
| | - Milena Baldauf
- Department of Plant Biology, Technische Universitaet Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Ahmed H Hassan
- Department of Plant Biology, Technische Universitaet Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Tobias Kruse
- Department of Plant Biology, Technische Universitaet Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia.
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5
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Kalimuthu P, Kruse T, Bernhardt PV. A highly sensitive and stable electrochemical nitrate biosensor. Electrochim Acta 2021. [DOI: 10.1016/j.electacta.2021.138480] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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6
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Ruth JC, Spormann AM. Enzyme Electrochemistry for Industrial Energy Applications—A Perspective on Future Areas of Focus. ACS Catal 2021. [DOI: 10.1021/acscatal.1c00708] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- John C. Ruth
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Alfred M. Spormann
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
- Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305, United States
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7
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Electrocatalysis of ferricyanide reduction mediated by electron transfer through the DNA duplex: Kinetic analysis by thin layer voltammetry. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.06.117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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8
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Kalimuthu P, Wojtkiewicz AM, Szaleniec M, Bernhardt PV. Electrocatalytic Hydroxylation of Sterols by Steroid C25 Dehydrogenase from Sterolibacterium denitrificans. Chemistry 2018; 24:7710-7717. [PMID: 29573289 DOI: 10.1002/chem.201800616] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 03/22/2018] [Indexed: 12/20/2022]
Abstract
The electrochemically driven catalysis of the complex molybdoenzyme steroid C25 dehydrogenase (S25DH) from the β-Proteobacterium Sterolibacterium denitrificans is reported. S25DH catalyses the oxygen-independent regioselective hydroxylation of the tertiary C25 atom of sterols and also their derivatives. Cholest-4-en-3-one is a native substrate for S25DH, which produces 25-hydroxycholest-4-en-3-one as a product of catalytic turnover. Cholecalciferol (vitD3 ) is also a substrate. S25DH was immobilised on a modified gold working electrode with the co-adsorbent chitosan. The complexes ferricyanide ([Fe(CN)6 ]3- ) and ferrocenium methanol (FM+ ) are effective artificial electron acceptors from S25DH and act as mediators of electron transfer between the electrode and the enzyme. 2-Hydroxypropyl-β-cyclodextrin (HPCD) was employed as a sterol solubiliser, in addition to 2-methoxyethanol. The catalytic activity varied, depending upon the concentration of solubiliser in the reaction mixture. Parallel studies with [Fe(CN)6 ]3- as a chemical (as opposed to electrochemical) oxidant coupled to HPLC analysis show that S25DH is capable of oxidising both vitD3 and its less stable isomer, pre-vitD3 , and that the former substrate is stabilised by HPCD.
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Affiliation(s)
- Palraj Kalimuthu
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
| | - Agnieszka M Wojtkiewicz
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30 239, Krakow, Poland
| | - Maciej Szaleniec
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30 239, Krakow, Poland
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
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9
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Musameh MM, Dunn CJ, Uddin MH, Sutherland TD, Rapson TD. Silk provides a new avenue for third generation biosensors: Sensitive, selective and stable electrochemical detection of nitric oxide. Biosens Bioelectron 2018; 103:26-31. [DOI: 10.1016/j.bios.2017.12.019] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/30/2017] [Accepted: 12/13/2017] [Indexed: 01/05/2023]
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10
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Kalimuthu P, Hsiao J, Nair RP, Kappler U, Bernhardt PV. Bioelectrocatalysis of Sulfite Dehydrogenase from
Sinorhizobium meliloti
with Its Physiological Cytochrome Electron Partner. ChemElectroChem 2017. [DOI: 10.1002/celc.201700838] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Palraj Kalimuthu
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Australia
| | - Ju‐Chun Hsiao
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Australia
| | | | - Ulrike Kappler
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Australia
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11
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Cobalt cage complexes as mediators of protein electron transfer. J Biol Inorg Chem 2016; 22:775-788. [DOI: 10.1007/s00775-016-1427-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 12/05/2016] [Indexed: 01/10/2023]
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12
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Kalimuthu P, Ringel P, Kruse T, Bernhardt PV. Direct electrochemistry of nitrate reductase from the fungus Neurospora crassa. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1506-1513. [DOI: 10.1016/j.bbabio.2016.04.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 04/01/2016] [Indexed: 01/08/2023]
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13
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Corrie SR, Coffey JW, Islam J, Markey KA, Kendall MAF. Blood, sweat, and tears: developing clinically relevant protein biosensors for integrated body fluid analysis. Analyst 2016; 140:4350-64. [PMID: 25909342 DOI: 10.1039/c5an00464k] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Biosensors are being developed to provide rapid, quantitative, diagnostic information to clinicians in order to help guide patient treatment, without the need for centralised laboratory assays. The success of glucose monitoring is a key example of where technology innovation has met a clinical need at multiple levels – from the pathology laboratory all the way to the patient's home. However, few other biosensor devices are currently in routine use. Here we review the challenges and opportunities regarding the integration of biosensor techniques into body fluid sampling approaches, with emphasis on the point-of-care setting.
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Affiliation(s)
- S R Corrie
- The University of Queensland, Australian Institute for Bioengineering and Nanotechnology, Delivery of Drugs and Genes Group (D2G2), St Lucia, Queensland 4072, Australia.
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14
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Voitechovič E, Bratov A, Abramova N, Razumienė J, Kirsanov D, Legin A, Lakshmi D, Piletsky S, Whitcombe M, Ivanova-Mitseva P. Development of label-free impedimetric platform based on new conductive polyaniline polymer and three-dimensional interdigitated electrode array for biosensor applications. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.05.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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15
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Rosenstein JK, Lemay SG, Shepard KL. Single-molecule bioelectronics. WILEY INTERDISCIPLINARY REVIEWS. NANOMEDICINE AND NANOBIOTECHNOLOGY 2015; 7:475-93. [PMID: 25529538 PMCID: PMC4476964 DOI: 10.1002/wnan.1323] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 08/04/2014] [Accepted: 10/29/2014] [Indexed: 01/08/2023]
Abstract
Experimental techniques that interface single biomolecules directly with microelectronic systems are increasingly being used in a wide range of powerful applications, from fundamental studies of biomolecules to ultra-sensitive assays. In this study, we review several technologies that can perform electronic measurements of single molecules in solution: ion channels, nanopore sensors, carbon nanotube field-effect transistors, electron tunneling gaps, and redox cycling. We discuss the shared features among these techniques that enable them to resolve individual molecules, and discuss their limitations. Recordings from each of these methods all rely on similar electronic instrumentation, and we discuss the relevant circuit implementations and potential for scaling these single-molecule bioelectronic interfaces to high-throughput arrayed sensing platforms.
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Affiliation(s)
| | - Serge G Lemay
- MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands
| | - Kenneth L Shepard
- Departments of Electrical and Biomedical Engineering, Columbia University, New York, NY, USA
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16
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Britz D, Strutwolf J. Digital simulation of chronoamperometry at a disk electrode under a flat polymer film containing an enzyme. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2014.11.117] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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17
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Rapson TD, Warneke S, Musameh MM, Dacres H, Macdonald BCT, Trowell SC. Conversion of nitrous oxide to nitrogen by cobalt-substituted myoglobin. RSC Adv 2015. [DOI: 10.1039/c5ra15036a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Turning myoglobin into a nitrous oxide reductase.
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18
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Chen KI, Challinor VL, Kielmann L, Sharpe PC, De Voss JJ, Kappler U, McEwan AG, Bernhardt PV. Electrochemically mediated enantioselective reduction of chiral sulfoxides. J Biol Inorg Chem 2014; 20:395-402. [PMID: 25410832 DOI: 10.1007/s00775-014-1215-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 11/02/2014] [Indexed: 10/24/2022]
Abstract
The respiratory DMSO reductase from Rhodobacter capsulatus catalyzes the reduction of dimethyl sulfoxide to dimethyl sulfide. Herein, we have utilized this Mo enzyme as an enantioselective catalyst to generate optically pure sulfoxides (methyl p-tolyl sulfoxide, methyl phenyl sulfoxide and phenyl vinyl sulfoxide) from racemic starting materials. A hexaaminecobalt coordination compound in its divalent oxidation state was employed as the mediator of electron transfer between the working electrode and DMSO reductase to continually reactivate the enzyme after turnover. In all cases, chiral HPLC analysis of the reaction mixture revealed that the S-sulfoxide was reduced more rapidly leading to enrichment or isolation of the R isomer.
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Affiliation(s)
- Kuan-I Chen
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
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19
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Modeling and Simulation of Enzymatic Biofuel Cells with Three-Dimensional Microelectrodes. ENERGIES 2014. [DOI: 10.3390/en7074694] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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20
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Kalimuthu P, Fischer-Schrader K, Schwarz G, Bernhardt PV. A sensitive and stable amperometric nitrate biosensor employing Arabidopsis thaliana nitrate reductase. J Biol Inorg Chem 2014; 20:385-93. [DOI: 10.1007/s00775-014-1171-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 06/05/2014] [Indexed: 11/28/2022]
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21
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Kalimuthu P, Kappler U, Bernhardt PV. Catalytic Voltammetry of the Molybdoenzyme Sulfite Dehydrogenase from Sinorhizobium meliloti. J Phys Chem B 2014; 118:7091-9. [DOI: 10.1021/jp503963z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Palraj Kalimuthu
- School of Chemistry and Molecular
Biosciences, University of Queensland, Brisbane, 4072, Australia
| | - Ulrike Kappler
- School of Chemistry and Molecular
Biosciences, University of Queensland, Brisbane, 4072, Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular
Biosciences, University of Queensland, Brisbane, 4072, Australia
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22
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Mathwig K, Aartsma TJ, Canters GW, Lemay SG. Nanoscale methods for single-molecule electrochemistry. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2014; 7:383-404. [PMID: 25000819 DOI: 10.1146/annurev-anchem-062012-092557] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The development of experiments capable of probing individual molecules has led to major breakthroughs in fields ranging from molecular electronics to biophysics, allowing direct tests of knowledge derived from macroscopic measurements and enabling new assays that probe population heterogeneities and internal molecular dynamics. Although still somewhat in their infancy, such methods are also being developed for probing molecular systems in solution using electrochemical transduction mechanisms. Here we outline the present status of this emerging field, concentrating in particular on optical methods, metal-molecule-metal junctions, and electrochemical nanofluidic devices.
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Affiliation(s)
- Klaus Mathwig
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, the Netherlands; ,
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23
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Digital simulation of chronoamperometry at an electrode within a hemispherical polymer drop containing an enzyme: comparison of a hemispherical with a flat disk electrode. Biosens Bioelectron 2013; 50:269-77. [PMID: 23871876 DOI: 10.1016/j.bios.2013.06.059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 06/24/2013] [Accepted: 06/27/2013] [Indexed: 02/06/2023]
Abstract
Current-time and steady state current behaviour was simulated for the cases of a hemispherical and flat inlaid disk electrodes located under a hemispherical polymer drop containing an enzyme which converts a substrate diffusing into the drop into a product that is electroactive at the electrode. As well, a cylindrical electrode with length much greater than its diameter and coated with a layer of polymer/enzyme was treated. The ratio of steady state currents at the hemispherical to the disk electrode is not, as has sometimes been assumed, always equal to π/2; indeed this is only approached for polymer drops with large spillover ratio, that is, having a radius much larger than that of the electrodes. Steady state currents for all electrode geometries (including the cylinder) go through a maximum for some spillover ratio and then approach a constant value for larger spillover ratios. This constant value is the same as that for the diffusion limited current in a semi-infinite medium. For a cylindrical electrode, the steady state current tends towards zero for large spillover ratios.
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24
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Kalimuthu P, Heath MD, Santini JM, Kappler U, Bernhardt PV. Electrochemically driven catalysis of Rhizobium sp. NT-26 arsenite oxidase with its native electron acceptor cytochrome c552. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:112-20. [PMID: 23891971 DOI: 10.1016/j.bbabio.2013.07.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 07/05/2013] [Accepted: 07/19/2013] [Indexed: 10/26/2022]
Abstract
We describe the catalytic voltammograms of the periplasmic arsenite oxidase (Aio) from the chemolithoautotrophic bacterium Rhizobium sp. str. NT-26 that oxidizes arsenite to arsenate. Electrochemistry of the enzyme was accomplished using its native electron transfer partner, cytochrome c552 (cyt c552), as a mediator. The protein cyt c552 adsorbed on a mercaptoundecanoic acid (MUA) modified Au electrode exhibited a stable, reversible one-electron voltammetric response at +275mV vs NHE (pH6). In the presence of arsenite and Aio the voltammetry of cyt c552 is transformed from a transient response to an amplified sigmoidal (steady state) wave consistent with an electro-catalytic system. Digital simulation was performed using a single set of parameters for all catalytic voltammetries obtained at different sweep rates and various substrate concentrations. The obtained kinetic constants from digital simulation provide new insight into the kinetics of the NT-26 Aio catalytic mechanism.
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Affiliation(s)
- Palraj Kalimuthu
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
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25
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Kalimuthu P, Fischer-Schrader K, Schwarz G, Bernhardt PV. Mediated Electrochemistry of Nitrate Reductase from Arabidopsis thaliana. J Phys Chem B 2013; 117:7569-77. [DOI: 10.1021/jp404076w] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Palraj Kalimuthu
- School of Chemistry and Molecular
Biosciences, University of Queensland,
Brisbane, 4072, Australia
| | - Katrin Fischer-Schrader
- Institute of Biochemistry, Department of Chemistry & Center for Molecular Medicine, Cologne University, Zülpicherstr. 47, 50674 Köln, Germany
| | - Günter Schwarz
- Institute of Biochemistry, Department of Chemistry & Center for Molecular Medicine, Cologne University, Zülpicherstr. 47, 50674 Köln, Germany
| | - Paul V. Bernhardt
- School of Chemistry and Molecular
Biosciences, University of Queensland,
Brisbane, 4072, Australia
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26
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Jugder BE, Welch J, Aguey-Zinsou KF, Marquis CP. Fundamentals and electrochemical applications of [Ni–Fe]-uptake hydrogenases. RSC Adv 2013. [DOI: 10.1039/c3ra22668a] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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27
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Kalimuthu P, Leimkühler S, Bernhardt PV. Catalytic Electrochemistry of Xanthine Dehydrogenase. J Phys Chem B 2012; 116:11600-7. [DOI: 10.1021/jp307374z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Palraj Kalimuthu
- School of Chemistry and Molecular
Biosciences, University of Queensland,
Brisbane 4072, Australia
| | - Silke Leimkühler
- Institut für Biochemie
und Biologie, Universität Potsdam, 14476 Potsdam, Germany
| | - Paul V. Bernhardt
- School of Chemistry and Molecular
Biosciences, University of Queensland,
Brisbane 4072, Australia
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28
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Popivker I, Zilbermann I, Maimon E, Cohen H, Meyerstein D. The one-electron reduction of a multi-centred iron(III) polyoxometallate. A pulse radiolysis study. INORG CHEM COMMUN 2011. [DOI: 10.1016/j.inoche.2011.05.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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29
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Rothwell SA, O'Neill RD. Effects of applied potential on the mass of non-conducting poly(ortho-phenylenediamine) electro-deposited on EQCM electrodes: comparison with biosensor selectivity parameters. Phys Chem Chem Phys 2011; 13:5413-21. [PMID: 21359356 DOI: 10.1039/c0cp02341h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An electrochemical quartz-crystal microbalance (EQCM) was used to determine the mass of poly-(o-phenylenediamine) (PoPD) layers electro-deposited at different applied potentials in neutral buffered monomer solution, conditions that produce the insulating form of the polymer used as a permselective membrane in biosensor applications. There was a systematic increase in the total, steady state PoPD mass deposited for fixed applied potentials from 0.05 to 0.6 V vs. SCE, followed by a plateau up to 0.8 V. Comparison of PoPD mass and permselectivity parameters indicates that the ability of the passivating form of PoPD to block interference species in biosensor applications is not related in a simple way to the mass of material deposited on the surface. Instead, effects of the applied electropolymerisation potential in driving the electro-oxidation of oPD dimers and oligomers formed during the electro-deposition process are likely to have a more direct impact on the selectivity characteristics of the PoPD layer. The results highlight the usefulness of apparent permeabilities, especially of ascorbic acid, in revealing differences between PoPD layers electro-deposited under different conditions.
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Affiliation(s)
- Sharon A Rothwell
- UCD School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
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30
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Bernhardt PV. Exploiting the versatility and selectivity of Mo enzymes with electrochemistry. Chem Commun (Camb) 2011; 47:1663-73. [DOI: 10.1039/c0cc03681a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Rapson TD, Kappler U, Hanson GR, Bernhardt PV. Short circuiting a sulfite oxidising enzyme with direct electrochemistry: Active site substitutions and their effect on catalysis and electron transfer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:108-18. [DOI: 10.1016/j.bbabio.2010.09.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 09/06/2010] [Accepted: 09/15/2010] [Indexed: 10/19/2022]
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32
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Chen KI, McEwan AG, Bernhardt PV. Cobalt hexaamine mediated electrocatalytic voltammetry of dimethyl sulfoxide reductase: driving force effects on catalysis. J Biol Inorg Chem 2010; 16:227-34. [DOI: 10.1007/s00775-010-0719-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 10/11/2010] [Indexed: 11/28/2022]
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33
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Kalimuthu P, Tkac J, Kappler U, Davis JJ, Bernhardt PV. Highly Sensitive and Stable Electrochemical Sulfite Biosensor Incorporating a Bacterial Sulfite Dehydrogenase. Anal Chem 2010; 82:7374-9. [DOI: 10.1021/ac101493y] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Palraj Kalimuthu
- Centre for Metals in Biology, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia, and Department of Chemistry, University of Oxford, South Parks Road, Oxford, U.K
| | - Jan Tkac
- Centre for Metals in Biology, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia, and Department of Chemistry, University of Oxford, South Parks Road, Oxford, U.K
| | - Ulrike Kappler
- Centre for Metals in Biology, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia, and Department of Chemistry, University of Oxford, South Parks Road, Oxford, U.K
| | - Jason J. Davis
- Centre for Metals in Biology, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia, and Department of Chemistry, University of Oxford, South Parks Road, Oxford, U.K
| | - Paul V. Bernhardt
- Centre for Metals in Biology, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia, and Department of Chemistry, University of Oxford, South Parks Road, Oxford, U.K
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34
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Lehr J, Williamson BE, Barrière F, Downard AJ. Dependence of catalytic activity and long-term stability of enzyme hydrogel films on curing time. Bioelectrochemistry 2010; 79:142-6. [DOI: 10.1016/j.bioelechem.2009.12.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2009] [Revised: 11/09/2009] [Accepted: 12/04/2009] [Indexed: 11/30/2022]
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35
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Powell HV, Schnippering M, Cheung M, Macpherson JV, Mackenzie SR, Stavros VG, Unwin PR. Probing Redox Reactions of Immobilized Cytochrome c Using Evanescent Wave Cavity Ring-Down Spectroscopy in a Thin-Layer Electrochemical Cell. Chemphyschem 2010; 11:2985-91. [DOI: 10.1002/cphc.201000213] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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36
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Hollmann F, Arends I, Buehler K. Biocatalytic Redox Reactions for Organic Synthesis: Nonconventional Regeneration Methods. ChemCatChem 2010. [DOI: 10.1002/cctc.201000069] [Citation(s) in RCA: 206] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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37
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Yang W, Ratinac K, Ringer S, Thordarson P, Gooding J, Braet F. Kohlenstoffnanomaterialien für Biosensoren: Nanoröhren oder Graphen - was eignet sich besser? Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.200903463] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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38
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Yang W, Ratinac K, Ringer S, Thordarson P, Gooding J, Braet F. Carbon Nanomaterials in Biosensors: Should You Use Nanotubes or Graphene? Angew Chem Int Ed Engl 2010; 49:2114-38. [DOI: 10.1002/anie.200903463] [Citation(s) in RCA: 1192] [Impact Index Per Article: 85.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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39
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Kohlmann C, Greiner L, Leitner W, Wandrey C, Lütz S. Ionic liquids as performance additives for electroenzymatic syntheses. Chemistry 2010; 15:11692-700. [PMID: 19777513 DOI: 10.1002/chem.200901046] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Electroenzymatic syntheses combine oxidoreductase-catalysed reactions with electrochemical reactant supply. The use of ionic liquids as performance additives can contribute to overcoming existing limitations of these syntheses. Here, we report on the influence of different water-miscible ionic liquids on critical parameters such as conductivity, biocatalyst activity and stability or substrate solubility for three typical electroenzymatic syntheses. In these investigations promising ionic liquids were identified and have been used as additives for batch electrolyses on preparative scale for the three electroenzymatic systems. It was possible to improve the space-time-yield for the electrochemical regeneration of NADPH by a factor of three. For an amino acid oxidase catalysed resolution of a methionine racemate with ferrocene-mediated electrochemical regeneration of the enzyme-bound cofactor FAD a 50% increase in space time yield and 140% increase in catalyst utilisation (TTN) were achieved. Furthermore, for the chloroperoxidase-catalysed synthesis of (R)-phenylmethylsulfoxide with electrochemical generation of the required cosubstrate H2O2 the space time yield and the catalyst utilisation were improved by a factor of up to 4.2 depending on the ionic liquids used.
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Affiliation(s)
- Christina Kohlmann
- Institute of Biotechnology 2, Forschungszentrum Jülich, 52425 Jülich, Germany
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40
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Immobilization of the hyperthermophilic hydrogenase from Aquifex aeolicus bacterium onto gold and carbon nanotube electrodes for efficient H2 oxidation. J Biol Inorg Chem 2009; 14:1275-88. [DOI: 10.1007/s00775-009-0572-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Accepted: 07/04/2009] [Indexed: 10/20/2022]
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41
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Rothwell SA, Kinsella ME, Zain ZM, Serra PA, Rocchitta G, Lowry JP, O'Neill RD. Contributions by a novel edge effect to the permselectivity of an electrosynthesized polymer for microbiosensor applications. Anal Chem 2009; 81:3911-8. [PMID: 19371060 DOI: 10.1021/ac900162c] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Pt electrodes of different sizes (2 x 10(-5)-2 x 10(-2) cm(2)) and geometries (disks and cylinders) were coated with the ultrathin non-conducting form of poly(o-phenylenediamine), PPD, using amperometric electrosynthesis. Analysis of the ascorbic acid (AA) and H(2)O(2) apparent permeabilities for these Pt/PPD sensors revealed that the PPD deposited near the electrode insulation (Teflon or glass edge) was not as effective as the bulk surface PPD for blocking AA access to the Pt substrate. This discovery impacts on the design of implantable biosensors where electrodeposited polymers, such as PPD, are commonly used as the permselective barrier to block electroactive interference by reducing agents present in the target medium. The undesirable "edge effect" was particularly marked for small disk electrodes which have a high edge density (ratio of PPD-insulation edge length to electrode area), but was essentially absent for cylinder electrodes with a length of >0.2 mm. Sample biosensors, with a configuration based on these findings (25 microm diameter Pt fiber cylinders) and designed for brain neurotransmitter L-glutamate, behaved well in vitro in terms of Glu sensitivity and AA blocking.
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Affiliation(s)
- Sharon A Rothwell
- UCD School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
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42
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Chen KI, McEwan AG, Bernhardt PV. Mediated electrochemistry of dimethyl sulfoxide reductase from Rhodobacter capsulatus. J Biol Inorg Chem 2008; 14:409-19. [DOI: 10.1007/s00775-008-0458-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 11/26/2008] [Indexed: 11/29/2022]
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43
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Direct catalytic electrochemistry of sulfite dehydrogenase: Mechanistic insights and contrasts with related Mo enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:1319-25. [DOI: 10.1016/j.bbabio.2008.06.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 06/06/2008] [Accepted: 06/06/2008] [Indexed: 11/21/2022]
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44
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Pellissier M, Zigah D, Barrière F, Hapiot P. Optimized preparation and scanning electrochemical microscopy analysis in feedback mode of glucose oxidase layers grafted onto conducting carbon surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:9089-9095. [PMID: 18624418 DOI: 10.1021/la801150c] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
An optimized immobilization procedure based on the electroreduction of aryldiazonium salt followed by covalent attachment of a cross-linked hydrogel was used to graft glucose oxidase on a carbon surface. Scanning electrochemical microscopy (SECM) and cyclic voltammetry were used to follow the construction steps of the modified electrode. By adjusting the compactness of the layer through the electrografting reaction, the penetration of the mediator through the layer can be controlled to allow the monitoring of the enzymatic activity by both cyclic voltammetry and SECM in feedback mode. The enzymatic activity of the film is finally characterized by SECM.
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45
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Léger C, Bertrand P. Direct Electrochemistry of Redox Enzymes as a Tool for Mechanistic Studies. Chem Rev 2008; 108:2379-438. [DOI: 10.1021/cr0680742] [Citation(s) in RCA: 594] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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46
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Pellissier M, Barrière F, Downard AJ, Leech D. Improved stability of redox enzyme layers on glassy carbon electrodes via covalent grafting. Electrochem commun 2008. [DOI: 10.1016/j.elecom.2008.03.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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47
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Protein electrodes with direct electrochemical communication. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2008; 109:19-64. [PMID: 17928972 DOI: 10.1007/10_2007_083] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
Electrochemistry using direct electron transfer between an electrode and a protein or an enzyme has developed into a means for studying biological redox reactions and for bioanalytics, biosynthesis and bioenergetics. This review summarizes recent work on direct protein electrochemistry with special emphasis on our results in bioelectrocatalysis using isolated enzymes and enzyme-protein couples.
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48
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Designing sensitive and selective polymer/enzyme composite biosensors for brain monitoring in vivo. Trends Analyt Chem 2008. [DOI: 10.1016/j.trac.2007.11.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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49
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Neff PA, Serr A, Wunderlich BK, Bausch AR. Label-Free Electrical Determination of Trypsin Activity by a Silicon-on-Insulator Based Thin Film Resistor. Chemphyschem 2007; 8:2133-7. [PMID: 17722222 DOI: 10.1002/cphc.200700279] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A silicon-on-insulator (SOI) based thin film resistor is employed for the label-free determination of enzymatic activity. We demonstrate that enzymes, which cleave biological polyelectrolyte substrates, can be detected by the sensor. As an application, we consider the serine endopeptidase trypsin, which cleaves poly-L-lysine (PLL). We show that PLL adsorbs quasi-irreversibly to the sensor and is digested by trypsin directly at the sensor surface. The created PLL fragments are released into the bulk solution due to kinetic reasons. This results in a measurable change of the surface potential allowing for the determination of trypsin concentrations down to 50 ng mL(-1). Chymotrypsin is a similar endopeptidase with a different specificity, which cleaves PLL with a lower efficiency as compared to trypsin. The activity of trypsin is analyzed quantitatively employing a kinetic model for enzyme-catalyzed surface reactions. Moreover, we have demonstrated the specific inactivation of trypsin by a serine protease inhibitor, which covalently binds to the active site of the enzyme.
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Affiliation(s)
- Petra A Neff
- Lehrstuhl für Biophysik-E22, Technische Universität München, Germany
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50
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Modifications of Poly(o-phenylenediamine) Permselective Layer on Pt-Ir for Biosensor Application in Neurochemical Monitoring. SENSORS 2007. [DOI: 10.3390/s7040420] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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