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Ciobotaru IC, Oprea D, Ciobotaru CC, Enache TA. Low-Cost Plant-Based Metal and Metal Oxide Nanoparticle Synthesis and Their Use in Optical and Electrochemical (Bio)Sensors. Biosensors (Basel) 2023; 13:1031. [PMID: 38131791 PMCID: PMC10741781 DOI: 10.3390/bios13121031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/06/2023] [Accepted: 12/13/2023] [Indexed: 12/23/2023]
Abstract
Technological progress has led to the development of analytical tools that promise a huge socio-economic impact on our daily lives and an improved quality of life for all. The use of plant extract synthesized nanoparticles in the development and fabrication of optical or electrochemical (bio)sensors presents major advantages. Besides their low-cost fabrication and scalability, these nanoparticles may have a dual role, serving as a transducer component and as a recognition element, the latter requiring their functionalization with specific components. Different approaches, such as surface modification techniques to facilitate precise biomolecule attachment, thereby augmenting recognition capabilities, or fine tuning functional groups on nanoparticle surfaces are preferred for ensuring stable biomolecule conjugation while preserving bioactivity. Size optimization, maximizing surface area, and tailored nanoparticle shapes increase the potential for robust interactions and enhance the transduction. This article specifically aims to illustrate the adaptability and effectiveness of these biosensing platforms in identifying precise biological targets along with their far-reaching implications across various domains, spanning healthcare diagnostics, environmental monitoring, and diverse bioanalytical fields. By exploring these applications, the article highlights the significance of prioritizing the use of natural resources for nanoparticle synthesis. This emphasis aligns with the worldwide goal of envisioning sustainable and customized biosensing solutions, emphasizing heightened sensitivity and selectivity.
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Affiliation(s)
- Iulia Corina Ciobotaru
- National Institute of Materials Physics, 405A Atomistilor, 077125 Magurele, Romania; (I.C.C.); (D.O.); (C.C.C.)
| | - Daniela Oprea
- National Institute of Materials Physics, 405A Atomistilor, 077125 Magurele, Romania; (I.C.C.); (D.O.); (C.C.C.)
- Faculty of Physics, University of Bucharest, 405 Atomistilor, 077125 Magurele, Romania
| | | | - Teodor Adrian Enache
- National Institute of Materials Physics, 405A Atomistilor, 077125 Magurele, Romania; (I.C.C.); (D.O.); (C.C.C.)
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Bunea MC, Enache TA, Diculescu VC. In situ Electrochemical Evaluation of the Interaction of dsDNA with the Proteasome Inhibitor Anticancer Drug Bortezomib. Molecules 2023; 28:molecules28073277. [PMID: 37050039 PMCID: PMC10096380 DOI: 10.3390/molecules28073277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 03/29/2023] [Accepted: 04/04/2023] [Indexed: 04/08/2023] Open
Abstract
Bortezomib is an inhibitor of proteasomes and an anti-cancer drug. Although bortezomib is considered a safe drug, as confirmed by cytotoxicity assays, recent reports highlighted the possibility of interaction between bortezomib and cellular components, with detrimental long-term effects. The evaluation of the interaction between bortezomib and dsDNA was investigated in bulk solution and using a dsDNA electrochemical biosensor. The binding of bortezomib to dsDNA involved its electroactive centers and led to small morphological modifications in the dsDNA double helix, which were electrochemically identified through changes in the guanine and adenine residue oxidation peaks and confirmed by electrophoretic and spectrophotometric measurements. The redox product of bortezomib amino group oxidation was electrochemically generated in situ on the surface of the dsDNA electrochemical biosensor. The redox product of bortezomib was shown to interact primarily with guanine residues, preventing their oxidation and leading to the formation of bortezomib–guanine adducts, which was confirmed by control experiments with polyhomonucleotides electrochemical biosensors and mass spectrometry. An interaction mechanism between dsDNA and bortezomib is proposed, and the formation of the bortezomib redox product–guanine adduct explained.
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Affiliation(s)
| | - Teodor Adrian Enache
- National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania
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Bunea MC, Diculescu VC, Enculescu M, Oprea D, Enache TA. Influence of the Photodegradation of Azathioprine on DNA and Cells. Int J Mol Sci 2022; 23:ijms232214438. [PMID: 36430909 PMCID: PMC9692341 DOI: 10.3390/ijms232214438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/17/2022] [Accepted: 11/18/2022] [Indexed: 11/22/2022] Open
Abstract
Azathioprine (AZA) is a pharmacologic immunosuppressive agent administrated in various conditions such as autoimmune disease or to prevent the rejection of organ transplantation. The mechanism of action is based on its biologically active metabolite 6-mercaptopurine (6-MP), which is converted, among others, into thioguanine nucleotides capable of incorporating into replicating DNA, which may act as a strong UV chromophore and trigger DNA oxidation. The interaction between azathioprine and DNA, before and after exposure to solar simulator radiation, was investigated using UV-vis spectrometry and differential pulse voltammetry at a glassy carbon electrode. The results indicated that the interaction of AZA with UV radiation was pH-dependent and occurred with the formation of several metabolites, which induced oxidative damage in DNA, and the formation of DNA-metabolite adducts. Moreover, the viability assays obtained for the L929 cell culture showed that both azathioprine and degraded azathioprine induced a decrease in cell proliferation.
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Affiliation(s)
| | | | - Monica Enculescu
- National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania
| | - Daniela Oprea
- National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania
- Faculty of Physics, University of Bucharest, Atomistilor 405, 077125 Magurele, Romania
| | - Teodor Adrian Enache
- National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania
- Correspondence:
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David M, Şerban A, Adrian Enache T, Florescu M. Electrochemical quantification of levothyroxine at disposable screen-printed electrodes. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.116240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Bunea MC, Diculescu VC, Enculescu M, Iovu H, Enache TA. Redox Mechanism of Azathioprine and Its Interaction with DNA. Int J Mol Sci 2021; 22:ijms22136805. [PMID: 34202734 PMCID: PMC8268956 DOI: 10.3390/ijms22136805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/16/2021] [Accepted: 06/16/2021] [Indexed: 01/24/2023] Open
Abstract
The electrochemical behavior and the interaction of the immunosuppressive drug azathioprine (AZA) with deoxyribonucleic acid (DNA) were investigated using voltammetric techniques, mass spectrometry (MS), and scanning electron microscopy (SEM). The redox mechanism of AZA on glassy carbon (GC) was investigated using cyclic and differential pulse (DP) voltammetry. It was proven that the electroactive center of AZA is the nitro group and its reduction mechanism is a diffusion-controlled process, which occurs in consecutive steps with formation of electroactive products and involves the transfer of electrons and protons. A redox mechanism was proposed and the interaction of AZA with DNA was also investigated. Morphological characterization of the DNA film on the electrode surface before and after interaction with AZA was performed using scanning electron microscopy. An electrochemical DNA biosensor was employed to study the interactions between AZA and DNA with different concentrations, incubation times, and applied potential values. It was shown that the reduction of AZA molecules bound to the DNA layer induces structural changes of the DNA double strands and oxidative damage, which were recognized through the occurrence of the 8-oxo-deoxyguanosine oxidation peak. Mass spectrometry investigation of the DNA film before and after interaction with AZA also demonstrated the formation of AZA adducts with purine bases.
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Affiliation(s)
- Mihaela-Cristina Bunea
- Laboratory of Multifunctional Materials and Structures, National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania; (M.-C.B.); (V.-C.D.); (M.E.)
- Advanced Polymer Materials Group, University Politehnica of Bucharest, 1-7 Gh. Polizu, 011061 Bucharest, Romania;
| | - Victor-Constantin Diculescu
- Laboratory of Multifunctional Materials and Structures, National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania; (M.-C.B.); (V.-C.D.); (M.E.)
| | - Monica Enculescu
- Laboratory of Multifunctional Materials and Structures, National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania; (M.-C.B.); (V.-C.D.); (M.E.)
| | - Horia Iovu
- Advanced Polymer Materials Group, University Politehnica of Bucharest, 1-7 Gh. Polizu, 011061 Bucharest, Romania;
| | - Teodor Adrian Enache
- Laboratory of Multifunctional Materials and Structures, National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania; (M.-C.B.); (V.-C.D.); (M.E.)
- Correspondence:
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de Jesus CSH, Enache TA, Diculescu VC. Charge transfer reaction mechanisms of epoxyketone and boronated peptides at glassy carbon and boron doped diamond electrodes. J Electroanal Chem (Lausanne) 2020; 878:114733. [PMID: 33020701 PMCID: PMC7526604 DOI: 10.1016/j.jelechem.2020.114733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 11/28/2022]
Abstract
The ubiquitin-proteasome system regulates the level of proteins within cells through controlled proteolysis. In some diseases, the system function is dysregulated turning the ubiquitin-proteasome complex into a target for drug development. The redox behavior of proteasome inhibitors, epoxyketone and boronated peptides carfilzomib, oprozomib and delanzomib was investigated by voltammetric methods using glassy carbon and boron doped diamond electrodes. It was showed that the oxidation of epoxyketone peptides carfilzomib and oprozomib occurred in one step at glassy carbon electrode surface while at boron doped diamond two consecutive charge transfer reactions due to different adsorption orientation at the electrode surface were observed. The moieties of these peptides, involved in the oxidation process, were morpholine for carfilzomib and thiazole for oprozomib. For the boronated peptide delanzomib, two irreversible and independent redox processes, oxidation at +0.80 V and reduction at −1.40 V were identified in neutral media at both electrodes. The oxidation reaction occurred at the amino group close to the pyridine moiety of delanzomib with the transfer of one electron and one proton whereas the reduction process takes place at pyridine ring in a two-electrons two-protons mechanism. Redox mechanisms were proposed and the implications on the proteasome inhibition discussed. Electranalysis of proteasome inhibitor peptides and anticancer drugs. Carfilzomib and oprozomib epoxiketones, and boronated delanzomib peptides. Redox behavior at glassy carbon and boron doped diamond electrodes.. Redox mechanisms proposed and implications discussed.
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Affiliation(s)
| | - Teodor Adrian Enache
- National Institute of Material Physics, Atomistilor 405A, 077125 Magurele, Romania
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Chiorcea-Paquim AM, Enache TA, De Souza Gil E, Oliveira-Brett AM. Natural phenolic antioxidants electrochemistry: Towards a new food science methodology. Compr Rev Food Sci Food Saf 2020; 19:1680-1726. [PMID: 33337087 DOI: 10.1111/1541-4337.12566] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 03/26/2020] [Accepted: 03/31/2020] [Indexed: 11/27/2022]
Abstract
Natural phenolic compounds are abundant in the vegetable kingdom, occurring mainly as secondary metabolites in a wide variety of chemical structures. Around 10,000 different plant phenolic derivatives have been isolated and identified. This review provides an exhaustive overview concerning the electron transfer reactions in natural polyphenols, from the point of view of their in vitro antioxidant and/or pro-oxidant mode of action, as well as their identification in highly complex matrixes, for example, fruits, vegetables, wine, food supplements, relevant for food quality control, nutrition, and health research. The accurate assessment of polyphenols' redox behavior is essential, and the application of the electrochemical methods in routine quality control of natural products and foods, where the polyphenols antioxidant activity needs to be quantified in vitro, is of the utmost importance. The phenol moiety oxidation pathways and the effect of substituents and experimental conditions on their electrochemical behavior will be reviewed. The fundamental principles concerning the redox behavior of natural polyphenols, specifically flavonoids and other benzopyran derivatives, phenolic acids and ester derivatives, quinones, lignins, tannins, lignans, essential oils, stilbenes, curcuminoids, and chalcones, will be described. The final sections will focus on the electroanalysis of phenolic antioxidants in natural products and the electroanalytical evaluation of in vitro total antioxidant capacity.
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Affiliation(s)
| | - Teodor Adrian Enache
- CEMMPRE, Department of Chemistry, University of Coimbra, Coimbra, 3004-535, Portugal
| | - Eric De Souza Gil
- CEMMPRE, Department of Chemistry, University of Coimbra, Coimbra, 3004-535, Portugal.,Faculdade de Farmácia, Universidade Federal de Goiás, Setor Universitário, Goiânia, Goiás, Brasil
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Abstract
The interaction of proteins with free radicals leads, among other types of damages, to the production of stable carbonyl groups, which can be used as a quantification of oxidative stress at proteins level. The aim of this study was the development of an electrochemical sensor for the detection of carbonyl groups in proteins oxidized by reactive oxygen species. Its working principle is based on the redox properties of dinitrophenylhydrazine (DNPH). BSA was used as a model protein and its oxidation achieved through Fenton reactions. Using differential pulse voltammetry at glassy carbon electrode, the electrochemical behavior of DNPH and of the native and oxidized BSA was investigated in solution. It has been shown that the hydrazine moiety of the DNPH is the electroactive center and is responsible for carbonyl complexation. Special attention was paid to the immobilization of the DNPH in order to retain its redox properties, and this was achieved on a mixed 4-styrenesulfonic acid-nafion matrix. The sensor's surface characterization and the detection of carbonyl groups in oxidized protein were performed by voltammetry, Fourier-transformed infrared spectroscopy and scanning electron microscopy while the voltammetric results were confirmed by surface plasmon resonance measurements. It has been shown that upon interaction with carbonyl groups of the oxidized protein, the oxidation peak of the hydrazine moiety of DNPH decreases as a function of incubation time and protein concentration. The sensor sensitivity was 0.015 nmol carbonyl per mg of oxidized protein and detection limits of 50 μg oxidized BSA and 0.75 pmol carbonyls.
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Affiliation(s)
- Teodor Adrian Enache
- National Institute of Materials Physics , Atomistilor 405A , 077125 , Magurele , Romania
| | - Elena Matei
- National Institute of Materials Physics , Atomistilor 405A , 077125 , Magurele , Romania
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Issaad FZ, Fernandes IPG, Enache TA, Mouats C, Oliveira‐Brett AM. Honey and Pollen Phenolic Composition, Antioxidant Capacity, and DNA Protecting Properties. ELECTROANAL 2018. [DOI: 10.1002/elan.201800752] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Fatima Zohra Issaad
- Department of ChemistryFaculty of Science and TechnologyUniversity of Coimbra 3004-535 Coimbra Portugal
- Unité de Recherche de Chimie de l'Environnement et Moléculaire Structurale, CHEMSFaculté des Sciences Exactes, Campus Chaabet Erssas Université Constantine 1 25000 Constantine Algeria
- Centre de Recherche en Biotechnologie,CRBt, BPE 73 Ali Mendjeli, Nouvelle Ville 25000 Constantine Algeria
| | - Isabel P. G. Fernandes
- Department of ChemistryFaculty of Science and TechnologyUniversity of Coimbra 3004-535 Coimbra Portugal
| | - Teodor Adrian Enache
- Department of ChemistryFaculty of Science and TechnologyUniversity of Coimbra 3004-535 Coimbra Portugal
| | - Chabane Mouats
- Unité de Recherche de Chimie de l'Environnement et Moléculaire Structurale, CHEMSFaculté des Sciences Exactes, Campus Chaabet Erssas Université Constantine 1 25000 Constantine Algeria
| | - Ana Maria Oliveira‐Brett
- Department of ChemistryFaculty of Science and TechnologyUniversity of Coimbra 3004-535 Coimbra Portugal
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Chiorcea-Paquim AM, Enache TA, Oliveira-Brett AM. Electrochemistry of Alzheimer Disease Amyloid Beta Peptides. Curr Med Chem 2018; 25:4066-4083. [PMID: 29446720 DOI: 10.2174/0929867325666180214112536] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 05/18/2017] [Accepted: 05/18/2017] [Indexed: 11/22/2022]
Abstract
Alzheimer's disease (AD) is a widespread form of dementia that is estimated to affect 44.4 million people worldwide. AD pathology is closely related to the accumulation of amyloid beta (Aβ) peptides in fibrils and plagues, the small oligomeric intermediate species formed during the Aβ peptides aggregation presenting the highest neurotoxicity. This review discusses the recent advances on the Aβ peptides electrochemical characterization. The Aβ peptides oxidation at a glassy carbon electrode occurs in one or two steps, depending on the amino acid sequence, length and content. The first electron transfer reaction corresponds to the tyrosine Tyr10 amino acid residue oxidation, and the second to all three histidine (His6, His13 and His14) and one methionine (Met35) amino acid residues. The Aβ peptides aggregation and amyloid fibril formation are electrochemically detected via the electroactive amino acids oxidation peak currents decrease that occurs in a time dependent manner. The Aβ peptides redox behaviour is correlated with changes in the adsorption morphology from initially random coiled structures, corresponding to the Aβ peptide monomers in random coil or in α-helix conformations, to aggregates, protofibrils and two types of fibrils, corresponding to the Aβ peptides in a β-sheet configuration, observed by atomic force microscopy. Electrochemical studies of Aβ peptides aggregation, mediated by the interaction with metal ions, particularly zinc, copper and iron, and different methodologies concerning the detection of Aβ peptide biomarkers of AD in biological fluids, using electrochemical biosensors, are also discussed.
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Affiliation(s)
- Ana-Maria Chiorcea-Paquim
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535, Coimbra, Portugal
| | - Teodor Adrian Enache
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535, Coimbra, Portugal
| | - Ana Maria Oliveira-Brett
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535, Coimbra, Portugal
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Enache TA, Chiorcea-Paquim AM, Oliveira-Brett AM. Amyloid Beta Peptide VHHQ, KLVFF, and IIGLMVGGVV Domains Involved in Fibrilization: AFM and Electrochemical Characterization. Anal Chem 2018; 90:2285-2292. [PMID: 29314823 DOI: 10.1021/acs.analchem.7b04686] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The time-dependent structural modifications and oxidation behavior of specifically chosen five short amyloid beta (Aβ) peptides, Aβ1-16, Aβ1-28, Aβ10-20, Aβ12-28, and Aβ17-42, fragments of the complete human Aβ1-40 peptide, were investigated by atomic force microscopy (AFM) and voltammetry. The objective was to determine the influence of different Aβ domains (VHHQ that contains electroactive histidine H residues, KLVFF that is the peptide hydrophobic aggregation core, and IIGLMVGGVV that is the C-terminus hydrophobic region), and of Aβ peptide hydrophobicity, in the fibrilization mechanism. The short Aβ peptides absence of aggregation or the time-dependent aggregation mechanisms, at room temperature, in free chloride media, within the time window from 0 to 48 h, were established by AFM via changes in their adsorption morphology, and by differential pulse voltammetry, via modifications of the amino acid residues oxidation peak currents. The first oxidation peak was of tyrosine Y residue and the second peak was of histidine H and methionine M residues oxidation. A correlation between the presence of an intact highly hydrophobic KLVFF aggregation core and the time-dependent changes on the Aβ peptides aggregation was found. The hydrophobic C-terminal domain IIGLMVGGVV, present in the Aβ1-40 peptide, also contributed to accelerate the formation of Aβ1-40 peptide aggregates and fibrils.
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Affiliation(s)
- Teodor Adrian Enache
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra , 3004-535, Coimbra, Portugal
| | - Ana-Maria Chiorcea-Paquim
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra , 3004-535, Coimbra, Portugal
| | - Ana Maria Oliveira-Brett
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra , 3004-535, Coimbra, Portugal
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Enache TA, Oliveira-Brett AM. Alzheimer's disease amyloid beta peptides in vitro electrochemical oxidation. Bioelectrochemistry 2016; 114:13-23. [PMID: 27855361 DOI: 10.1016/j.bioelechem.2016.11.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 11/02/2016] [Accepted: 11/03/2016] [Indexed: 12/29/2022]
Abstract
The oxidative behaviour of the human amyloid beta (Aβ1-40 and Aβ1-42) peptides and a group of similar peptides: control inverse (Aβ40-1 and Aβ42-1), mutants (Aβ1-40Phe10 and Aβ1-40Nle35), rat Aβ1-40Rat, and fragments (Aβ1-28, Aβ1-16, Aβ10-20, Aβ12-28, and Aβ17-42), in solution or adsorbed, at a glassy carbon electrode, by cyclic and differential pulse voltammetry, were investigated and compared. Structurally the Aβ1-40 and Aβ1-42 sequences contain five electroactive amino acid residues, one tyrosine (Tyr10), three histidines (His6, His13 and His14) and one methionine (Met35). The Aβ peptide 3D structure influenced the exposure of the redox residues to the electrode surface and their oxidation peak currents. Depending on the amino acid sequence length and content, the Aβ peptides gave one or two oxidation peaks. The first electron transfer reaction corresponded to the tyrosine amino acid residue oxidation, and the second to both histidines and methionine amino acid residues. The highest contribution to the second oxidation peak current was from His13, followed by His14 and His6 residues, and Met35 residue had the lowest contribution. The Aβ peptides electron transfer depended on peptide hydrophobicity and 3D structure, the redox residues position in the sequence, the redox residues close to N-termini giving the highest oxidation peak currents.
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Affiliation(s)
- Teodor Adrian Enache
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Ana Maria Oliveira-Brett
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal.
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Enache TA, Oliveira-Brett AM. Electrochemical evaluation of glutathione S-transferase kinetic parameters. Bioelectrochemistry 2014; 101:46-51. [PMID: 25086278 DOI: 10.1016/j.bioelechem.2014.07.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 07/08/2014] [Accepted: 07/13/2014] [Indexed: 11/27/2022]
Abstract
Glutathione S-transferases (GSTs), are a family of enzymes belonging to the phase II metabolism that catalyse the formation of thioether conjugates between the endogenous tripeptide glutathione and xenobiotic compounds. The voltammetric behaviour of glutathione (GSH), 1-chloro-2,4-dinitrobenzene (CDNB) and glutathione S-transferase (GST), as well as the catalytic conjugation reaction of GSH to CDNB by GST was investigated at room temperature, T=298.15K (25°C), at pH6.5, for low concentration of substrates and enzyme, using differential pulse (DP) voltammetry at a glassy carbon electrode. Only GSH can be oxidized; a sensitivity of 0.14nA/μM and a LOD of 6.4μM were obtained. The GST kinetic parameter electrochemical evaluation, in relation to its substrates, GSH and CDNB, using reciprocal Michaelis-Menten and Lineweaver-Burk double reciprocal plots, was determined. A value of KM~100μM was obtained for either GSH or CDNB, and Vmax varied between 40 and 60μmol/min per mg of GST.
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Zatloukalová M, Enache TA, Křen V, Ulrichová J, Vacek J, Oliveira-Brett AM. Effect of 3-O-Galloyl Substitution on the Electrochemical Oxidation of Quercetin and Silybin Galloyl Esters at Glassy Carbon Electrode. ELECTROANAL 2013. [DOI: 10.1002/elan.201300102] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Oliveira SCB, Santarino IB, Enache TA, Nunes C, Laranjinha J, Barbosa RM, Oliveira-Brett AM. Human colon adenocarcinoma HT-29 cell: electrochemistry and nicotine stimulation. Bioelectrochemistry 2013; 94:30-8. [PMID: 23774106 DOI: 10.1016/j.bioelechem.2013.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 05/14/2013] [Accepted: 05/17/2013] [Indexed: 11/30/2022]
Abstract
Recently, it was demonstrated that colorectal cancer HT-29 cells can secrete epinephrine (adrenaline) in an autocrine manner to auto-stimulate cellular growth by adrenoreceptors activation, and that this secretion is enhanced by nicotine, showing an indirect relation between colorectal cancer and tobacco. The electrochemical behaviour of human colon adenocarcinoma HT-29 cells from a colorectal adenocarcinoma cell line, the hormone and neurotransmitter epinephrine, and nicotine, were investigated by cyclic voltammetry, using indium tin oxide (ITO), glassy carbon (GC) and screen printed carbon (SPC) electrodes. The oxidation of the HT-29 cells, previously grown onto ITO or SPC surfaces, followed an irreversible oxidation process that involved the formation of a main oxidation product that undergoes irreversible reduction, as in the epinephrine oxidation mechanism. The effect of nicotine stimulation of the HT-29 cells was also investigated. Nicotine, at different concentration levels 1, 2 and 15 mM, was introduced in the culture medium and an increase with incubation time, 0 to 3h and 30 min, of the HT-29 cells oxidation and reduction peaks was observed. The interaction of nicotine with the HT-29 cells stimulated the epinephrine secretion causing an increase in epinephrine release concentration, and enabling the conclusion that epinephrine and nicotine play an important role in the colorectal tumour growth.
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Affiliation(s)
- S C B Oliveira
- Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3004-535 Coimbra, Portugal
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Gil EDS, Enache TA, Oliveira-Brett AM. Redox behaviour of verbascoside and rosmarinic acid. Comb Chem High Throughput Screen 2013; 16:92-7. [PMID: 23092164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 07/16/2012] [Accepted: 08/03/2012] [Indexed: 06/01/2023]
Abstract
The electrochemical oxidation mechanisms of rosmarinic acid (RA) and verbascoside (VB), both caffeic acid esters with two catechol moieties, were investigated. The redox mechanism is associated with the oxidation of the catechol groups, and was studied over a wide pH range by cyclic, differential pulse and square wave voltammetry, using a glassy carbon electrode. The voltammetric study revealed that both molecules, RA and VB, are reversibly oxidized in two successive pH-dependent steps each with the transfer of two electrons and two protons. Moreover, it was found that the first oxidation step is associated with the caffeic acid moiety, whereas the second oxidation step corresponds to the oxidation in VB of the hydroxytyrosol group and in RA of the 3,4-dihydroxyphenyl lactic acid residue.
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Affiliation(s)
- Eric de Souza Gil
- Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, Coimbra, Portugal
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Adrian Enache T, Fatibello-Filho O, Maria Oliveira-Brett A. Electrochemical Behavior of Triflusal, Aspirin and their Metabolites at Glassy Carbon and Boron Doped Diamond Electrodes. Comb Chem High Throughput Screen 2010; 13:569-77. [DOI: 10.2174/1386207311004070569] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2009] [Accepted: 12/30/2009] [Indexed: 11/22/2022]
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Enache TA, Chiorcea-Paquim AM, Fatibello-Filho O, Oliveira-Brett AM. Hydroxyl radicals electrochemically generated in situ on a boron-doped diamond electrode. Electrochem commun 2009. [DOI: 10.1016/j.elecom.2009.04.017] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Diculescu VC, Enache TA, Oliveira‐Brett AM. Electrochemical Oxidation at a Glassy Carbon Electrode of the Anti‐Arrhythmia Drug Disopyramide. ANAL LETT 2007. [DOI: 10.1080/00032710701564151] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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