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Medina D, Omanakuttan B, Nguyen R, Alwarsh E, Walgama C. Electrochemical Probing of Human Liver Subcellular S9 Fractions for Drug Metabolite Synthesis. Metabolites 2024; 14:429. [PMID: 39195525 DOI: 10.3390/metabo14080429] [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: 07/14/2024] [Revised: 07/24/2024] [Accepted: 07/30/2024] [Indexed: 08/29/2024] Open
Abstract
Human liver subcellular fractions, including liver microsomes (HLM), liver cytosol fractions, and S9 fractions, are extensively utilized in in vitro assays to predict liver metabolism. The S9 fractions are supernatants of human liver homogenates that contain both microsomes and cytosol, which include most cytochrome P450 (CYP) enzymes and soluble phase II enzymes such as glucuronosyltransferases and sulfotransferases. This study reports on the direct electrochemistry and biocatalytic features of redox-active enzymes in S9 fractions for the first time. We investigated the electrochemical properties of S9 films by immobilizing them onto a high-purity graphite (HPG) electrode and performing cyclic voltammetry under anaerobic (Ar-saturated) and aerobic (O2-saturated) conditions. The heterogeneous electron transfer rate between the S9 film and the HPG electrode was found to be 14 ± 3 s-1, with a formal potential of -0.451 V vs. Ag/AgCl reference electrode, which confirmed the electrochemical activation of the FAD/FMN cofactor containing CYP450-reductase (CPR) as the electron receiver from the electrode. The S9 films have also demonstrated catalytic oxygen reduction under aerobic conditions, identical to HLM films attached to similar electrodes. Additionally, we investigated CYP activity in the S9 biofilm for phase I metabolism using diclofenac hydroxylation as a probe reaction and identified metabolic products using liquid chromatography-mass spectrometry (LC-MS). Investigating the feasibility of utilizing liver S9 fractions in such electrochemical assays offers significant advantages for pharmacological and toxicological evaluations of new drugs in development while providing valuable insights for the development of efficient biosensor and bioreactor platforms.
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Affiliation(s)
- Daphne Medina
- Department of Physical & Applied Sciences, University of Houston-Clear Lake, 2700 Bay Area Boulevard, Houston, TX 77058, USA
| | - Bhavana Omanakuttan
- Department of Physical & Applied Sciences, University of Houston-Clear Lake, 2700 Bay Area Boulevard, Houston, TX 77058, USA
| | - Ricky Nguyen
- Department of Physical & Applied Sciences, University of Houston-Clear Lake, 2700 Bay Area Boulevard, Houston, TX 77058, USA
| | - Eman Alwarsh
- Department of Physical & Applied Sciences, University of Houston-Clear Lake, 2700 Bay Area Boulevard, Houston, TX 77058, USA
| | - Charuksha Walgama
- Department of Physical & Applied Sciences, University of Houston-Clear Lake, 2700 Bay Area Boulevard, Houston, TX 77058, USA
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Koroleva PI, Bulko TV, Agafonova LE, Shumyantseva VV. Catalytic and Electrocatalytic Mechanisms of Cytochromes P450 in the Development of Biosensors and Bioreactors. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1645-1657. [PMID: 38105030 DOI: 10.1134/s0006297923100176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 08/23/2023] [Accepted: 08/25/2023] [Indexed: 12/19/2023]
Abstract
Cytochromes P450 are a unique family of enzymes found in all Kingdoms of living organisms (animals, bacteria, plants, fungi, and archaea), whose main function is biotransformation of exogenous and endogenous compounds. The review discusses approaches to enhancing the efficiency of electrocatalysis by cytochromes P450 for their use in biotechnology and design of biosensors and describes main methods in the development of reconstituted and electrochemical catalytic systems based on the biochemical mechanism of cytochromes P450, as well as and modern trends for their practical application.
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Affiliation(s)
| | | | | | - Victoria V Shumyantseva
- Institute of Biomedical Chemistry, Moscow, 119121, Russia.
- Pirogov Russian National Research Medical University, Moscow, 117997, Russia
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Sun X, Sun J, Ye Y, Ji J, Sheng L, Yang D, Sun X. Metabolic pathway-based self-assembled Au@MXene liver microsome electrochemical biosensor for rapid screening of aflatoxin B1. Bioelectrochemistry 2023; 151:108378. [PMID: 36774719 DOI: 10.1016/j.bioelechem.2023.108378] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 01/26/2023]
Abstract
Cytochrome P450 enzymes (CYPs) catalyze the production of aflatoxin B1 (AFB1) metabolites, which play an important role in carcinogenesis. In this study, we report a simple electrochemical liver-microsome-based biosensor using a composite of gold nanoparticles adsorbed on MXene (Au@MXene) for rapid screening of AFB1. Rat liver microsomes (RLMs) were directly adsorbed on the Au@MXene nanocomposite. The high conductivity, large specific surface area, and good biocompatibility of the Au@MXene nanocomposite enabled the direct electron transfer between the RLMs and the electrode and maintained the biological activity of the enzyme in the RLMs to a large extent. The metabolic behavior of the RLM biosensor that was developed for the electrocatalyst of AFB1 to its hydroxylation metabolite aflatoxin M1 (AFM1) was confirmed. Based on the change in the electrical signal generated by this metabolic behavior, we established the relationship between AFB1 content and amperometric (I-t) current signal. When the AFB1 concentration ranged from 0.01 μM to 50 μM, the AFB1 concentration was linearly related to the electrical signal with a limit of detection of 2.8 nM. The results of the recovery experiments for corn samples showed that the recovery and accuracy of the sensor were consistent with the UPLC-MS/MS method.
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Affiliation(s)
- Xinyu Sun
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Collaborative Innovation Center of Food Safety and Quality Control, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Jiadi Sun
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Collaborative Innovation Center of Food Safety and Quality Control, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Yongli Ye
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Collaborative Innovation Center of Food Safety and Quality Control, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Jian Ji
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Collaborative Innovation Center of Food Safety and Quality Control, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Lina Sheng
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Collaborative Innovation Center of Food Safety and Quality Control, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Diaodiao Yang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Collaborative Innovation Center of Food Safety and Quality Control, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Xiulan Sun
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Collaborative Innovation Center of Food Safety and Quality Control, Jiangnan University, Wuxi, Jiangsu 214122, China.
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Sun X, Ye Y, Sun J, Tang L, Yang X, Sun X. Advances in the study of liver microsomes in the in vitro metabolism and toxicity evaluation of foodborne contaminants. Crit Rev Food Sci Nutr 2022; 64:3264-3278. [PMID: 36226776 DOI: 10.1080/10408398.2022.2131728] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Foodborne contaminants are closely related to anthropologic activities and represent an important food safety hazard. The study of metabolic transformation and toxic side effects of foodborne contaminants in the body is important for their safety assessment. Liver microsomes contain a variety of enzymes related to substance metabolism and biotransformation. An in vitro model simulating liver metabolic transformation is associated with a significant advantage in the study of the metabolic transformation mechanisms of contaminants. This review summarizes the recent progress in the application of liver microsomes in metabolic transformation and toxicity evaluation of various foodborne pollutants based on metabolic kinetics, molecular docking and enzyme inhibition studies. The purpose of this review is to distinguish the existing studies involving liver microsomes and provide strategies for their application in the future. Finally, the prospects and challenges of the liver microsomal model are discussed.
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Affiliation(s)
- Xinyu Sun
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Collaborative Innovation Center of Food Safety and Quality Control, Jiangnan University, Wuxi, Jiangsu, China
| | - Yongli Ye
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Collaborative Innovation Center of Food Safety and Quality Control, Jiangnan University, Wuxi, Jiangsu, China
| | - Jiadi Sun
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Collaborative Innovation Center of Food Safety and Quality Control, Jiangnan University, Wuxi, Jiangsu, China
| | - Lili Tang
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, Georgia, USA
| | - Xingxing Yang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Collaborative Innovation Center of Food Safety and Quality Control, Jiangnan University, Wuxi, Jiangsu, China
| | - Xiulan Sun
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Collaborative Innovation Center of Food Safety and Quality Control, Jiangnan University, Wuxi, Jiangsu, China
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Dharmaratne AC, Moulton JT, Niroula J, Walgama C, Mazumder S, Mohanty S, Krishnan S. Pyrenyl Carbon Nanotubes for Covalent Bilirubin Oxidase Biocathode Design: Should the Nanotubes be Carboxylated? ELECTROANAL 2020. [DOI: 10.1002/elan.201900564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Asantha C. Dharmaratne
- Department of Chemistry Oklahoma State University, Stillwater Oklahoma 74078 United States
| | - James T. Moulton
- Department of Chemistry Oklahoma State University, Stillwater Oklahoma 74078 United States
| | - Jinesh Niroula
- Department of Chemistry Oklahoma State University, Stillwater Oklahoma 74078 United States
| | - Charuksha Walgama
- Department of Chemistry Oklahoma State University, Stillwater Oklahoma 74078 United States
- Present Address: Department of Chemistry The University of Texas at Austin Austin TX 78712 United States
| | - Suman Mazumder
- Department of Chemistry Oklahoma State University, Stillwater Oklahoma 74078 United States
| | - Smita Mohanty
- Department of Chemistry Oklahoma State University, Stillwater Oklahoma 74078 United States
| | - Sadagopan Krishnan
- Department of Chemistry Oklahoma State University, Stillwater Oklahoma 74078 United States
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Walgama C, Pathiranage A, Akinwale M, Montealegre R, Niroula J, Echeverria E, McIlroy DN, Harriman TA, Lucca DA, Krishnan S. Buckypaper–Bilirubin Oxidase Biointerface for Electrocatalytic Applications: Buckypaper Thickness. ACS APPLIED BIO MATERIALS 2019; 2:2229-2236. [DOI: 10.1021/acsabm.9b00189] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Charuksha Walgama
- Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Anuruddha Pathiranage
- Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Mayowa Akinwale
- Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Roberto Montealegre
- Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Jinesh Niroula
- Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Elena Echeverria
- Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - David N. McIlroy
- Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Tres A. Harriman
- School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Don A. Lucca
- School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Sadagopan Krishnan
- Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
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Nerimetla R, Premaratne G, Liu H, Krishnan S. Improved electrocatalytic metabolite production and drug biosensing by human liver microsomes immobilized on amine-functionalized magnetic nanoparticles. Electrochim Acta 2018. [DOI: 10.1016/j.electacta.2018.05.085] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Screening Genotoxicity Chemistry with Microfluidic Electrochemiluminescent Arrays. SENSORS 2017; 17:s17051008. [PMID: 28467352 PMCID: PMC5469531 DOI: 10.3390/s17051008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 04/24/2017] [Accepted: 04/26/2017] [Indexed: 01/19/2023]
Abstract
This review describes progress in the development of electrochemiluminescent (ECL) arrays aimed at sensing DNA damage to identify genotoxic chemistry related to reactive metabolites. Genotoxicity refers to chemical or photochemical processes that damage DNA with toxic consequences. Our arrays feature DNA/enzyme films that form reactive metabolites of test chemicals that can subsequently react with DNA, thus enabling prediction of genotoxic chemical reactions. These high-throughput ECL arrays incorporating representative cohorts of human metabolic enzymes provide a platform for determining chemical toxicity profiles of new drug and environmental chemical candidates. The arrays can be designed to identify enzymes and enzyme cascades that produce the reactive metabolites. We also describe ECL arrays that detect oxidative DNA damage caused by metabolite-mediated reactive oxygen species. These approaches provide valuable high-throughput tools to complement modern toxicity bioassays and provide a more complete toxicity prediction for drug and chemical product development.
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Nerimetla R, Walgama C, Singh V, Hartson SD, Krishnan S. Mechanistic Insights into Voltage-Driven Biocatalysis of a Cytochrome P450 Bactosomal Film on a Self-Assembled Monolayer. ACS Catal 2017. [DOI: 10.1021/acscatal.6b03588] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rajasekhara Nerimetla
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Charuksha Walgama
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Vini Singh
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Steven D. Hartson
- Department
of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Sadagopan Krishnan
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
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Walgama C, Nerimetla R, Materer NF, Schildkraut D, Elman JF, Krishnan S. A Simple Construction of Electrochemical Liver Microsomal Bioreactor for Rapid Drug Metabolism and Inhibition Assays. Anal Chem 2015; 87:4712-8. [DOI: 10.1021/ac5044362] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Charuksha Walgama
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Rajasekhara Nerimetla
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Nicholas F. Materer
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Deniz Schildkraut
- Filmetrics Application Lab—Rochester, 250 Packett’s Landing, Fairport, New York 14450, United States
| | - James F. Elman
- Filmetrics Application Lab—Rochester, 250 Packett’s Landing, Fairport, New York 14450, United States
| | - Sadagopan Krishnan
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
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11
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Bioelectrochemistry as a tool for the study of aromatization of steroids by human aromatase. Electrochem commun 2015. [DOI: 10.1016/j.elecom.2015.01.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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12
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Nerimetla R, Walgama C, Ramanathan R, Krishnan S. Correlating the Electrochemical Kinetics of Myoglobin-Films to pH Dependent Meat Color. ELECTROANAL 2014. [DOI: 10.1002/elan.201300630] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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13
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Krishnan S, Walgama C. Electrocatalytic Features of a Heme Protein Attached to Polymer-Functionalized Magnetic Nanoparticles. Anal Chem 2013; 85:11420-6. [DOI: 10.1021/ac402421z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Sadagopan Krishnan
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Charuksha Walgama
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
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Wasalathanthri DP, Faria RC, Malla S, Joshi AA, Schenkman JB, Rusling JF. Screening reactive metabolites bioactivated by multiple enzyme pathways using a multiplexed microfluidic system. Analyst 2013; 138:171-8. [PMID: 23095952 PMCID: PMC3509269 DOI: 10.1039/c2an35993f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A multiplexed, microfluidic platform to detect reactive metabolites is described, and its performance is illustrated for compounds metabolized by oxidative and bioconjugation enzymes in multi-enzyme pathways to mimic natural human drug metabolism. The device features four 8-electrode screen printed carbon arrays coated with thin films of DNA, a ruthenium-polyvinylpyridine (RuPVP) catalyst, and multiple enzyme sources including human liver microsomes (HLM), cytochrome P450 (cyt P450) 1B1 supersomes, microsomal epoxide hydrolase (EH), human S9 liver fractions (Hs9) and N-acetyltransferase (NAT). Arrays are arranged in parallel to facilitate multiple compound screening, enabling up to 32 enzyme reactions and measurements in 20-30 min. In the first step of the assay, metabolic reactions are achieved under constant flow of oxygenated reactant solutions by electrode driven natural catalytic cycles of cyt P450s and cofactor-supported bioconjugation enzymes. Reactive metabolites formed in the enzyme reactions can react with DNA. Relative DNA damage is measured in the second assay step using square wave voltammetry (SWV) with RuPVP as catalyst. Studies were done on chemicals known to require metabolic activation to induce genotoxicity, and results reproduced known features of metabolite DNA-reactivity for the test compounds. Metabolism of benzo[a]pyrene (B[a]P) by cyt P450s and epoxide hydrolase showed an enhanced relative DNA damage rate for DNA compared to cyt P450s alone. DNA damage rates for arylamines by pathways featuring both oxidative and conjugative enzymes at pH 7.4 gave better correlation with rodent genotoxicity metric TD(50). Results illustrate the broad utility of the reactive metabolite screening device.
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Affiliation(s)
| | - Ronaldo C. Faria
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
- Departamento de Química, Universidade Federal de São Carlos, São Carlos, SP, Brazil
| | - Spundana Malla
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Amit A. Joshi
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - John B. Schenkman
- Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut 06032, United States
| | - James F. Rusling
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
- Departamento de Química, Universidade Federal de São Carlos, São Carlos, SP, Brazil
- NationalUniversity of Ireland at Galway, Ireland
- Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut 06032, United States
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Wasalathanthri DP, Malla S, Faria RC, Rusling JF. Electrochemical Activation of the Natural Catalytic Cycle of Cytochrome P450s in Human Liver Microsomes. ELECTROANAL 2012; 24:2049-2052. [PMID: 23626453 DOI: 10.1002/elan.201200373] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The natural catalytic cycle of cytochrome (cyt) P450 enzymes in human liver microsome (HLM) films was activated electrochemically via the electron transfer sequence electrode→cyt P450 reductase (CPR)→cyt P450. Cyclic voltammograms for HLM films had midpoint potentials of -0.50 V vs. SCE at pH 7.4 characteristic of CPR, not cyt P450s. HLM and CPR microsomes without cyt P450s did not electrocatalytically reduce H2O2, and did not shift midpoint potential when CO was added, also indicating that the peaks do not correspond to iron heme cyt P450 enzymes. Electrochemical activation of the natural cyt P450 cycle for substrate conversion via CPR in HLM films was confirmed by catalytic electrolysis in an electrochemical microfluidic array designed to generate and detect reactive metabolites by measuring their reactivity with DNA.
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Analysis of carbamazepine serum by differential pulse voltammetry (DPV) and comparison with fluorescence polarization immunoassay (FPIA): an animal study. Med Chem Res 2012. [DOI: 10.1007/s00044-012-9981-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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17
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Wasalathanthri DP, Mani V, Tang CK, Rusling JF. Microfluidic electrochemical array for detection of reactive metabolites formed by cytochrome P450 enzymes. Anal Chem 2011; 83:9499-506. [PMID: 22040095 DOI: 10.1021/ac202269t] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel, simple, rapid microfluidic array using bioelectronically driven cytochrome P450 enzyme catalysis for reactive metabolite screening is reported for the first time. The device incorporates an eight-electrode screen-printed carbon array coated with thin films of DNA, [Ru(bpy)(2)(PVP)(10)](ClO(4)) {RuPVP}, and rat liver microsomes (RLM) as enzyme sources. Catalysis features electron donation to cyt P450 reductase in the RLMs and subsequent cyt P450 reduction while flowing an oxygenated substrate solution past sensor electrodes. Metabolites react with DNA in the film if they are able, and damaged DNA is detected by catalytic square wave voltammetry (SWV) utilizing the RuPVP polymer. The microfluidic device was tested for a set of common pollutants known to form DNA-reactive metabolites. Logarithmic turnover rates based on SWV responses gave excellent correlation with the rodent liver TD(50) toxicity metric, supporting the utility of the device for toxicity screening. The microfluidic array gave much better S/N and reproducibility than single-electrode sensors based on similar principles.
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18
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Krishnan S, Wasalathanthri D, Zhao L, Schenkman JB, Rusling JF. Efficient bioelectronic actuation of the natural catalytic pathway of human metabolic cytochrome P450s. J Am Chem Soc 2011; 133:1459-65. [PMID: 21214177 PMCID: PMC3033457 DOI: 10.1021/ja108637s] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cytochrome (cyt) P450s comprise the enzyme superfamily responsible for human oxidative metabolism of a majority of drugs and xenobiotics. Electronic delivery of electrons to cyt P450s could be used to drive the natural catalytic cycle for fundamental investigations, stereo- and regioselective synthesis, and biosensors. We describe herein 30 nm nanometer-thick films on electrodes featuring excess human cyt P450s and cyt P450 reductase (CPR) microsomes that efficiently mimic the natural catalytic pathway for the first time. Redox potentials, electron-transfer rates, CO-binding, and substrate conversion rates confirmed that electrons are delivered from the electrode to CPR, which transfers them to cyt P450. The film system enabled electrochemical probing of the interaction between cyt P450 and CPR for the first time. Agreement of film voltammetry data with theoretical simulations supports a pathway featuring a key equilibrium redox reaction in the natural catalytic pathway between reduced CPR and cyt P450 occurring within a CPR-cyt P450 complex uniquely poised for substrate conversion.
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Sadeghi SJ, Fantuzzi A, Gilardi G. Breakthrough in P450 bioelectrochemistry and future perspectives. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1814:237-48. [DOI: 10.1016/j.bbapap.2010.07.010] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 07/04/2010] [Indexed: 11/25/2022]
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Krishnan S, Bajrami B, Mani V, Pan S, Rusling JF. Comparison of DNA-Reactive Metabolites from Nitrosamine and Styrene Using Voltammetric DNA/Microsomes Sensors. ELECTROANAL 2009; 21:1005-1013. [PMID: 23100998 DOI: 10.1002/elan.200804521] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Voltammetric sensors made with films of polyions, double-stranded DNA and liver microsomes adsorbed layer-by-layer onto pyrolytic graphite electrodes were evaluated for reactive metabolite screening. This approach features simple, inexpensive screening without enzyme purification for applications in drug or environmental chemical development. Cytochrome P450 enzymes (CYPs) in the liver microsomes were activated by an NADPH regenerating system or by electrolysis to metabolize model carcinogenic compounds nitrosamine and styrene. Reactive metabolites formed in the films were trapped as adducts with nucleobases on DNA. The DNA damage was detected by square-wave voltammetry (SWV) using [Formula: see text] as a DNA-oxidation catalyst. These sensors showed a larger rate of increase in signal vs. reaction time for a highly toxic nitrosamine than for the moderately toxic styrene due to more rapid reactive metabolite-DNA adduct formation. Results were consistent with reported in vivo TD(50) data for the formation of liver tumors in rats. Analogous polyion/ liver microsome films prepared on 500 nm silica nanoparticles (nanoreactors) and reacted with nitrosamine or styrene, provided LC-MS or GC analyses of metabolite formation rates that correlated well with sensor response.
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Affiliation(s)
- Sadagopan Krishnan
- Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060, USA
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