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Shiek SS, Sajai ST, Dsouza HS. Arsenic-induced toxicity and the ameliorative role of antioxidants and natural compounds. J Biochem Mol Toxicol 2023; 37:e23281. [PMID: 36550698 DOI: 10.1002/jbt.23281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 11/04/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022]
Abstract
Arsenic (As) poisoning has proven to be a major threat worldwide because of its toxic effects on the human body. As toxicity through drinking water is a global health concern. The toxicity of As is known to affect the liver, kidney, lungs, muscles, cardiovascular system, and nervous system and can even induce diabetes. Further As can cause skin lesions leading to notable diseases in the skin like Bowen's disease. Chronic exposure to As has caused many tragedies in Eastern, and several Southeast Asian and Latin American countries. Long-term exposure to As makes it an immediate threat that should be dealt with as a priority, and one of the ways to handle it may be with the use of antioxidants. In this review, we have discussed the natural and anthropogenic sources of As, its metabolism, pathophysiology, and mechanism of toxicity. Besides, we have also discussed some of the synthetic chelators and the ameliorative role of antioxidants and natural compounds in reducing As toxicity.
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Affiliation(s)
- Sadiya S Shiek
- Department of Biology, College of Science, United Arab Emirates University, United Arab Emirates
| | - Sanai T Sajai
- Manipal School of Life Sciences, Manipal Academy of Higher Education (MAHE), Manipal, Karnataka, India
| | - Herman S Dsouza
- Department of Radiation Biology and Toxicology, Manipal School of Life Sciences, Manipal Academy of Higher Education (MAHE), Manipal, Karnataka, India
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2
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NMR study of thiosulfate-assisted oxidation of L-cysteine. MENDELEEV COMMUNICATIONS 2023. [DOI: 10.1016/j.mencom.2023.01.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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3
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Chlorine Dioxide: Friend or Foe for Cell Biomolecules? A Chemical Approach. Int J Mol Sci 2022; 23:ijms232415660. [PMID: 36555303 PMCID: PMC9779649 DOI: 10.3390/ijms232415660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/28/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
This review examines the role of chlorine dioxide (ClO2) on inorganic compounds and cell biomolecules. As a disinfectant also present in drinking water, ClO2 helps to destroy bacteria, viruses, and some parasites. The Environmental Protection Agency EPA regulates the maximum concentration of chlorine dioxide in drinking water to be no more than 0.8 ppm. In any case, human consumption must be strictly regulated since, given its highly reactive nature, it can react with and oxidize many of the inorganic compounds found in natural waters. Simultaneously, chlorine dioxide reacts with natural organic matter in water, including humic and fulvic acids, forming oxidized organic compounds such as aldehydes and carboxylic acids, and rapidly oxidizes phenolic compounds, amines, amino acids, peptides, and proteins, as well as the nicotinamide adenine dinucleotide NADH, responsible for electron and proton exchange and energy production in all cells. The influence of ClO2 on biomolecules is derived from its interference with redox processes, modifying the electrochemical balances in mitochondrial and cell membranes. This discourages its use on an individual basis and without specialized monitoring by health professionals.
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Hayanti SY, Sholikin MM, Jayanegara A, Ulum MF, da Costa MA, Fitriawaty F, Surya S, Hadiatry MC, Asmarasari SA, Handiwirawan E, Anggraeny YN, Rohaeni ES, Ahmad SN, Bustami B, Aryogi A, Pamungkas D, Yusriani Y. Effect of supplementing L-cysteine and its group analogs on frozen semen quality of bulls: A meta-analysis. Vet World 2022; 15:2517-2524. [PMID: 36590123 PMCID: PMC9798054 DOI: 10.14202/vetworld.2022.2517-2524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 09/19/2022] [Indexed: 11/11/2022] Open
Abstract
Background and Aim The quality of frozen bull sperm after thawing is influenced by the primary diluent and antioxidant. This meta-analysis was conducted to determine the effect of supplementing L-cysteine and its group analogs on the quality of frozen bull sperm. Materials and Methods A total of 22 articles obtained from Google Scholar and Scopus were integrated into metadata. The effects of adding L-cysteine and its analogs (e.g., cysteine HCl and N-acetyl-L-cysteine), both of which are known as L-cysteine, were evaluated in this meta-analysis. The following parameters were examined: Abnormality, acrosome damage, acrosomal integrity, DNA damage, DNA integrity, malondialdehyde (MDA) content, plasma membrane integrity, pregnancy rate, progressive motility, sperm viability, and total motility. Data were analyzed using the mixed model methodology, with L-cysteine dosage as a fixed effect and different studies as random effects. Results L-cysteine supplementation significantly increased the total motility (p < 0.05) and MDA content of semen, following a linear pattern. Progressive motility, acrosomal integrity, and plasma membrane integrity were significantly increased, showing a quadratic pattern (p < 0.05). Abnormality and acrosome damage were significantly decreased (p < 0.05), following a quadratic and linear pattern, respectively. Other parameters remained unaffected by L-cysteine supplementation. L-cysteine and cysteine HCl significantly inhibited (p = 0.001) acrosome damage in thawed frozen sperm compared with control sperm. Conclusion Supplementing L-cysteine and its analog groups are recommended for freezing bull semen as it generally improves sperm quality.
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Affiliation(s)
- Sari Yanti Hayanti
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia,Corresponding author: Sari Yanti Hayanti, e-mail: Co-authors: MMS: , AJ: , MFU: , MAC: , FF: , SS: , MCH: , SAA: , EH: , YNA: , ESR: , SNA: , BB: , AA: , DP: , YY:
| | - Mohammad Miftakhus Sholikin
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia,Animal Feed and Nutrition Modelling Research Group, Faculty of Animal Science, IPB University, Bogor 16680, West Java, Indonesia
| | - Anuraga Jayanegara
- Animal Feed and Nutrition Modelling Research Group, Faculty of Animal Science, IPB University, Bogor 16680, West Java, Indonesia,Department of Nutrition and Feed Technology, Faculty of Animal Science, IPB University, Bogor 16680, West Java, Indonesia
| | - Mokhamad Fakhrul Ulum
- Division of Veterinary Reproduction, Obstetrics, and Gynaecology, Department of Veterinary Clinic, Reproduction, and Pathology, School of Veterinary Medicine and Biomedical Sciences, IPB University, Bogor, 16680, West Java, Indonesia
| | - Marchie Astrid da Costa
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Fitriawaty Fitriawaty
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Surya Surya
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Maureen Chrisye Hadiatry
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Santiananda Arta Asmarasari
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Eko Handiwirawan
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Yenny Nur Anggraeny
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Eni Siti Rohaeni
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Salfina Nurdin Ahmad
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Bustami Bustami
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Aryogi Aryogi
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Dicky Pamungkas
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
| | - Yenni Yusriani
- Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency of The Republic of Indonesia (BRIN), Cibinong Sciences Center, Cibinong, Bogor 16911, Indonesia
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Spero MA, Jones J, Lomenick B, Chou TF, Newman DK. Mechanisms of chlorate toxicity and resistance in Pseudomonas aeruginosa. Mol Microbiol 2022; 118:321-335. [PMID: 36271736 PMCID: PMC9589919 DOI: 10.1111/mmi.14972] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/31/2022] [Accepted: 08/04/2022] [Indexed: 11/28/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic bacterial pathogen that often encounters hypoxic/anoxic environments within the host, which increases its tolerance to many conventional antibiotics. Toward identifying novel treatments, we explored the therapeutic potential of chlorate, a pro-drug that kills hypoxic/anoxic, antibiotic-tolerant P. aeruginosa populations. While chlorate itself is relatively nontoxic, it is enzymatically reduced to the toxic oxidizing agent, chlorite, by hypoxically induced nitrate reductase. To better assess chlorate's therapeutic potential, we investigated mechanisms of chlorate toxicity and resistance in P. aeruginosa. We used transposon mutagenesis to identify genes that alter P. aeruginosa fitness during chlorate treatment, finding that methionine sulfoxide reductases (Msr), which repair oxidized methionine residues, support survival during chlorate stress. Chlorate treatment leads to proteome-wide methionine oxidation, which is exacerbated in a ∆msrA∆msrB strain. In response to chlorate, P. aeruginosa upregulates proteins involved in a wide range of functions, including metabolism, DNA replication/repair, protein repair, transcription, and translation, and these newly synthesized proteins are particularly vulnerable to methionine oxidation. The addition of exogenous methionine partially rescues P. aeruginosa survival during chlorate treatment, suggesting that widespread methionine oxidation contributes to death. Finally, we found that mutations that decrease nitrate reductase activity are a common mechanism of chlorate resistance.
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Affiliation(s)
- Melanie A. Spero
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Present address: Institute of Molecular Biology, University of Oregon, Eugene, OR, USA
| | - Jeff Jones
- Proteome Exploration Laboratory, Beckman Institute, Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Brett Lomenick
- Proteome Exploration Laboratory, Beckman Institute, Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Tsui-Fen Chou
- Proteome Exploration Laboratory, Beckman Institute, Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Dianne K. Newman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
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Xu MY, Lin YL, Zhang TY, Hu CY, Tang YL, Deng J, Xu B. Chlorine dioxide-based oxidation processes for water purification:A review. JOURNAL OF HAZARDOUS MATERIALS 2022; 436:129195. [PMID: 35739725 DOI: 10.1016/j.jhazmat.2022.129195] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 05/14/2022] [Accepted: 05/18/2022] [Indexed: 06/15/2023]
Abstract
Chlorine dioxide (ClO2) has emerged as a broad-spectrum, safe, and effective disinfectant due to its high oxidation efficiency and reduced formation of organochlorinated by-products during application. This article provides an updated overview of ClO2-based oxidation processes used in water treatment. A systematic review of scientific information and experimental data on ClO2-based water purification procedures is presented. Concerning ClO2-based oxidation derivative problems, the pros and cons of ClO2-based combined processes are assessed and disinfection by-product (DBP) control approaches are proposed. The kinetic and mechanistic data on ClO2 reactivity towards micropollutants are discussed. ClO2 selectively reacts with electron-rich moieties (anilines, phenols, olefins, and amines) and eliminates certain inorganic ions and microorganisms with high efficiency. The formation of chlorite and chlorate during the oxidation process is a crucial concern when utilizing ClO2. Future applications include the combination of ClO2 with ferrous ions, activated carbon, ozone, UV, visible light, or persulfate processes. The combined process can reduce by-product generation while still ensuring ClO2 sterilization and disinfection. Overall, this research could provide useful information and new insights into the application of ClO2-based technologies.
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Affiliation(s)
- Meng-Yuan Xu
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Yi-Li Lin
- Department of Safety, Health and Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 824, Taiwan, ROC
| | - Tian-Yang Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Chen-Yan Hu
- College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090, PR China
| | - Yu-Lin Tang
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Jing Deng
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, PR China
| | - Bin Xu
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
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7
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Smith DJ, Scapanski A, Herges G. The fate of sodium chlorite in simulated gastric and intestinal fluids and residues of chlorate in broiler chickens after oral administration of sodium chlorite. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2021; 39:242-255. [PMID: 34732111 DOI: 10.1080/19440049.2021.1992513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The fate of sodium [36Cl]chlorite in simulated intestinal fluids and residues of chlorate in broiler chickens fed 0, 10, 100, or 1000 mg•kg-1 of dietary sodium chlorite for 7 days was determined. [36Cl]Chlorite was stable in water and simulated intestinal fluid during 6 h incubations but was rapidly degraded to chlorine dioxide, sodium chloride, and sodium chlorate in simulated gastric fluids. Addition of starch, citrate, or soybean shifted the relative proportions of chloroxyanions formed; addition of ferrous chloride caused quantitative formation of sodium chloride in gastric and intestinal fluids. [36Cl]Chlorite underwent reductive transformation when fortified into chicken serum. Residues of chlorate in broiler chickens ranged from 3.5 to 374 ng•g-1 in gizzard, were <6.8 to 126 ng•g-1 in liver and were <7.2 to 190 ng•g-1 in muscle when slaughtered with no withdrawal period. Data are presented suggesting that reductive processes govern the fate of chlorite when present in closed biological systems.
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Affiliation(s)
- David J Smith
- USDA ARS, Edward T. Schafer Agricultural Research Center, Biosciences Research Laboratory, Fargo, ND, USA
| | - Abigail Scapanski
- USDA ARS, Edward T. Schafer Agricultural Research Center, Biosciences Research Laboratory, Fargo, ND, USA
| | - Grant Herges
- USDA ARS, Edward T. Schafer Agricultural Research Center, Biosciences Research Laboratory, Fargo, ND, USA
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Oxidation of Cysteinate Anions Immobilized in the Interlamellar Space of CaAl-Layered Double Hydroxide. MATERIALS 2021; 14:ma14051202. [PMID: 33806484 PMCID: PMC7961893 DOI: 10.3390/ma14051202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/22/2021] [Accepted: 03/01/2021] [Indexed: 12/02/2022]
Abstract
L-Cysteinate-intercalated CaAl-layered double hydroxide (LDH) was prepared by the co-precipitation method producing highly crystalline hydrocalumite phase with a well-pillared interlayer gallery. The obtained materials were characterized by X-ray diffractometry, IR as well as Raman spectroscopies. By performing interlamellar oxidation reactions with peracetic acid as oxidant, oxidation of cysteinate to cystinate in aqueous and cysteinate sulfenic acid in acetonic suspensions occurred. The oxidations could be performed under mild conditions, at room temperature, under neutral pH and in air. It has been shown that the transformation pathways are due to the presence of the layered structure, that is, the confined space of the LDH behaved as molecular reactor.
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Gan W, Huang S, Ge Y, Bond T, Westerhoff P, Zhai J, Yang X. Chlorite formation during ClO 2 oxidation of model compounds having various functional groups and humic substances. WATER RESEARCH 2019; 159:348-357. [PMID: 31108363 DOI: 10.1016/j.watres.2019.05.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 04/15/2019] [Accepted: 05/05/2019] [Indexed: 06/09/2023]
Abstract
Chlorine dioxide (ClO2) has been used as an alternative to chlorine in water purification to reduce the formation of halogenated by-products and give superior inactivation of microorganisms. However, the formation of chlorite (ClO2-) is a major consideration in the application of ClO2. In order to improve understanding in ClO2- formation kinetics and mechanisms, this study investigated the reactions of ClO2 with 30 model compounds, 10 humic substances and 2 surface waters. ClO2- yields were found to be dependent on the distribution of functional groups. ClO2 oxidation of amines, di- and tri-hydroxybenzenes at pH 7.0 had ClO2- yields >50%, while oxidation of olefins, thiols and benzoquinones had ClO2- yields <50%. ClO2- yields from humic substances depended on the ClO2 dose, pH and varied with different reaction intervals, which mirrored the behavior of the model compounds. Phenolic moieties served as dominant fast-reacting precursors (during the first 5 min of disinfection). Aromatic precursors (e.g., non-phenolic lignins or benzoquinones) contributed to ClO2- formation over longer reaction time (up to 24 h). The total antioxidant capacity (indication of the amount of electron-donating moieties) determined by the Folin-Ciocalteu method was a good indicator of ClO2-reactive precursors in waters, which correlated with the ClO2 demand of waters. Waters bearing high total antioxidant capacity tended to generate more ClO2- at equivalent ClO2 exposure, but the prediction in natural water should be conservative.
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Affiliation(s)
- Wenhui Gan
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Sirong Huang
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Yuexian Ge
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Tom Bond
- Department of Civil and Environmental Engineering, University of Surrey, Guildford, GU2 7XH, United Kingdom
| | - Paul Westerhoff
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, 85287-3005, United States
| | - Jiaxin Zhai
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Xin Yang
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou, 510275, China.
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Iron(III)–salen ion catalyzed s-oxidation of l-cysteine and s-alkyl-l-cysteines by H2O2: Spectral, kinetic and electrochemical study. Polyhedron 2019. [DOI: 10.1016/j.poly.2018.11.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Chlorate Specifically Targets Oxidant-Starved, Antibiotic-Tolerant Populations of Pseudomonas aeruginosa Biofilms. mBio 2018; 9:mBio.01400-18. [PMID: 30254119 PMCID: PMC6156191 DOI: 10.1128/mbio.01400-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The anaerobic growth and survival of bacteria are often correlated with physiological tolerance to conventional antibiotics, motivating the development of novel strategies targeting pathogens in anoxic environments. A key challenge is to identify drug targets that are specific to this metabolic state. Chlorate is a nontoxic compound that can be reduced to toxic chlorite by a widespread enzyme of anaerobic metabolism. We tested the antibacterial properties of chlorate against Pseudomonas aeruginosa, a pathogen that can inhabit hypoxic or anoxic microenvironments, including those that arise in human infection. Chlorate and the antibiotic tobramycin kill distinct metabolic populations in P. aeruginosa biofilms, where chlorate targets anaerobic cells that tolerate tobramycin. Chlorate is particularly effective against P. aeruginosalasR mutants, which are frequently isolated from human infections and more resistant to some antibiotics. This work suggests that chlorate may hold potential as an anaerobic prodrug. Nitrate respiration is a widespread mode of anaerobic energy generation used by many bacterial pathogens, and the respiratory nitrate reductase, Nar, has long been known to reduce chlorate to the toxic oxidizing agent chlorite. Here, we demonstrate the antibacterial activity of chlorate against Pseudomonas aeruginosa, a representative pathogen that can inhabit hypoxic or anoxic host microenvironments during infection. Aerobically grown P. aeruginosa cells are tobramycin sensitive but chlorate tolerant. In the absence of oxygen or an alternative electron acceptor, cells are tobramycin tolerant but chlorate sensitive via Nar-dependent reduction. The fact that chlorite, the product of chlorate reduction, is not detected in culture supernatants suggests that it may react rapidly and be retained intracellularly. Tobramycin and chlorate target distinct populations within metabolically stratified aggregate biofilms; tobramycin kills cells on the oxic periphery, whereas chlorate kills hypoxic and anoxic cells in the interior. In a matrix populated by multiple aggregates, tobramycin-mediated death of surface aggregates enables deeper oxygen penetration into the matrix, benefiting select aggregate populations by increasing survival and removing chlorate sensitivity. Finally, lasR mutants, which commonly arise in P. aeruginosa infections and are known to withstand conventional antibiotic treatment, are hypersensitive to chlorate. A lasR mutant shows a propensity to respire nitrate and reduce chlorate more rapidly than the wild type does, consistent with its heightened chlorate sensitivity. These findings illustrate chlorate’s potential to selectively target oxidant-starved pathogens, including physiological states and genotypes of P. aeruginosa that represent antibiotic-tolerant populations during infections.
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12
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Chipiso K, Simoyi RH. Kinetics and Mechanism of Oxidation of Methimazole by Chlorite in Slightly Acidic Media. J Phys Chem A 2016; 120:3767-79. [DOI: 10.1021/acs.jpca.6b02699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kudzanai Chipiso
- Department of Chemistry, Portland State University, Portland, Oregon 97207-0751, United States
| | - Reuben H. Simoyi
- Department of Chemistry, Portland State University, Portland, Oregon 97207-0751, United States
- School of Chemistry and Physics, University of KwaZulu-Natal, Westville Campus, Durban 4014, South Africa
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13
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Guo XF, Arceo J, Huge BJ, Ludwig KR, Dovichi NJ. Chemical cytometry of thiols using capillary zone electrophoresis-laser induced fluorescence and TMPAB-o-M, an improved fluorogenic reagent. Analyst 2016; 141:1325-30. [PMID: 26814594 PMCID: PMC4747679 DOI: 10.1039/c5an02116b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Low molecular weight thiol compounds play crucial roles in many physiological processes. Most methods for determination of thiol compounds are population-averaged; few methods for quantification of thiol compounds in single cells have been reported. We report an ultrasensitive method for determination of thiol compounds in single cells by use of 1,3,5,7-tetramethyl-8-phenyl-(2-maleimide)-difluoroboradiaza-s-indacene (TMPAB-o-M), a fluorogenic probe with useful spectral properties, coupled with capillary zone electrophoresis and laser induced fluorescence detection using a post-column sheath flow cuvette. TMPAB-o-M provides low background, high sensitivity, and excellent reactivity. After optimization of the separation method, we achieved baseline separation of labeled glutathione (GSH), cysteine (Cys), homocysteine, and γ-glutamylcysteine within 11 min, and produced concentration limits of detection from 10 to 20 pM and mass LODs of 65 to 100 zmol. The method was applied for analysis of thiol containing compounds in both cell homogenates and in single HCT-29 and MCF-10A cells. GSH was the main thiol, and Cys was also detected in both cell types. Cells were treated with N-ethylmaleimide, which significantly attenuated thiol levels.
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Affiliation(s)
- Xiao-Feng Guo
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA. and Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - Jennifer Arceo
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Bonnie Jaskowski Huge
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Katelyn R Ludwig
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Norman J Dovichi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
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Chipiso K, Simoyi RH. Electrochemistry-coupled to mass spectrometry in simulation of metabolic oxidation of methimazole: Identification and characterization of metabolites. J Electroanal Chem (Lausanne) 2016. [DOI: 10.1016/j.jelechem.2015.10.041] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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15
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Öğretmen F, İnanan BE, Kutluyer F, Kayim M. Effect of semen extender supplementation with cysteine on postthaw sperm quality, DNA damage, and fertilizing ability in the common carp (Cyprinus carpio). Theriogenology 2015; 83:1548-52. [DOI: 10.1016/j.theriogenology.2015.02.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 01/30/2015] [Accepted: 02/01/2015] [Indexed: 12/26/2022]
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16
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Chigwada T, Mbiya W, Chipiso K, Simoyi RH. S-oxygenation of thiocarbamides V: oxidation of tetramethylthiourea by chlorite in slightly acidic media. J Phys Chem A 2014; 118:5903-14. [PMID: 24922053 DOI: 10.1021/jp504018k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reaction between tetramethylthiourea (TTTU) and slightly acidic chlorite has been studied. The reaction is much faster than comparable oxidations of the parent thiourea compound as well as other substituted thioureas. The stoichiometry of the reaction in excess oxidant showed a complete desulfurization of the thiocarbamide to yield the corresponding urea and sulfate: 2ClO2(-) + (Me2N)2C ═ S + H2O → (Me2N)2C ═ O + SO4(2-) + 2Cl(-) + 2H(+). The reaction mechanism is unique in that the most stable metabolite before formation of the corresponding urea is the S-oxide. This is one of the rare occasions in which a low-molecular-weight S-oxide has been stabilized without the aid of large steric groups. ESI-MS data show almost quantitative formation of the S-oxide and negligible formation of the sulfinic and sulfonic acids. TTTU, in contrast to other substituted thioureas, can only stabilize intermediate oxoacids, before formation of sulfate, in the form of zwitterions. With a stoichiometric excess of TTTU over oxidant, the TTTU dimer is the predominant product. Chlorine dioxide, which is formed from the reaction of excess chlorite and HOCl, is a very important reactant in the overall mechanism. It reacts rapidly with TTTU to reform ClO2(-). Oxidation of TTTU by chlorite has a complex dependence on acid as a result of chlorous acid dissociation and protonation of the thiol group on TTTU in high-acid conditions, which renders the thiol center a less effective nucleophile.
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Affiliation(s)
- Tabitha Chigwada
- Department of Chemistry, Portland State University , Portland, Oregon 97207-0751, United States
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Bhattarai N, Stanbury DM. Oxidation of Cysteinesulfinic Acid by Hexachloroiridate(IV). J Phys Chem B 2014; 118:1097-101. [DOI: 10.1021/jp4116723] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Nootan Bhattarai
- Department of Chemistry and
Biochemistry, Auburn University, Auburn, Alabama 36849, United States
| | - David M. Stanbury
- Department of Chemistry and
Biochemistry, Auburn University, Auburn, Alabama 36849, United States
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18
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Kapungu GP, Rukweza G, Tran T, Mbiya W, Adigun R, Ndungu P, Martincigh B, Simoyi RH. Oxyhalogen–Sulfur Chemistry: Kinetics and Mechanism of Oxidation of Captopril by Acidified Bromate and Aqueous Bromine. J Phys Chem A 2013; 117:2704-17. [DOI: 10.1021/jp312672w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | - Thai Tran
- Department of Chemistry, Portland State University, Portland,
Oregon 97207-0751, United States
| | - Wilbes Mbiya
- Department of Chemistry, Portland State University, Portland,
Oregon 97207-0751, United States
| | - Risikat Adigun
- Department of Chemistry, Portland State University, Portland,
Oregon 97207-0751, United States
| | - Patrick Ndungu
- School of Chemistry
and Physics, University of KwaZulu-Natal, Westville Campus, Durban 4000, South Africa
| | - Bice Martincigh
- School of Chemistry
and Physics, University of KwaZulu-Natal, Westville Campus, Durban 4000, South Africa
| | - Reuben H. Simoyi
- Department of Chemistry, Portland State University, Portland,
Oregon 97207-0751, United States
- School of Chemistry
and Physics, University of KwaZulu-Natal, Westville Campus, Durban 4000, South Africa
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Nayak S, Brahma GS, Reddy KV. Kinetics and Mechanism of the Reaction of Dichlorotetraaquaruthenium(III) and Thiols. Aust J Chem 2012. [DOI: 10.1071/ch11352] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The formation of an intermediate ruthenium(iii) thiolate complex by the interaction of thiols, RSH (R = glutathione and l-cysteine) and dichlorotetraaquaruthenium(iii), [RuIIICl2(H2O)4]+, is reported in the temperature range 25–40°C. The kinetics and mechanism of formation of the intermediate complex were studied as a function of [RuIIICl2(H2O)4]+, [RSH], pH, ionic strength and temperature. Reduction of the intermediate complex takes place slowly and results in the corresponding disulfides RSSR and [RuIICl2(H2O)4]+. The results are interpreted in terms of a mechanism involving a rate-determining inner-sphere one-electron transfer from RSH to the oxidant used in the present investigation and a comparison of rate and equilibrium constants is presented with activation parameters.
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21
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Sippel KH, Genis C, Govindasamy L, Agbandje-McKenna M, Kiddle JJ, Tripp BC, McKenna R. Synchrotron Radiation Provides a Plausible Explanation for the Generation of a Free Radical Adduct of Thioxolone in Mutant Carbonic Anhydrase II. J Phys Chem Lett 2010; 1:2898-2902. [PMID: 20976122 PMCID: PMC2957018 DOI: 10.1021/jz100954h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Thioxolone acts as a prodrug in the presence of carbonic anhydrase II (CA II), whereby the molecule is cleaved by thioester hydrolysis to the carbonic anhydrase inhibitor, 4-mercaptobenzene-1,3-diol (TH0). Thioxolone was soaked into the proton transfer mutant H64A of CA II in an effort to capture a reaction intermediate via X-ray crystallography. Structure determination of the 1.2 Å resolution data revealed the TH0 had been modified to a 4,4'-disulfanediyldibenzene-1,3-diol, a product of crystallization conditions, and a zinc ligated 2,4-dihydroxybenzenesulfenic acid, most likely induced by radiation damage. Neither ligand was likely a result of an enzymatic mechanism.
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Affiliation(s)
- Katherine H. Sippel
- Department of Biochemistry and Molecular Biology, P.O. Box 100245, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Caroli Genis
- Department of Biochemistry and Molecular Biology, P.O. Box 100245, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Lakshmanan Govindasamy
- Department of Biochemistry and Molecular Biology, P.O. Box 100245, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Mavis Agbandje-McKenna
- Department of Biochemistry and Molecular Biology, P.O. Box 100245, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - James J. Kiddle
- Department of Chemistry Western Michigan University, Kalamazoo, Michigan 49008
| | - Brian C. Tripp
- Department of Chemistry Western Michigan University, Kalamazoo, Michigan 49008
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, P.O. Box 100245, College of Medicine, University of Florida, Gainesville, Florida 32610
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22
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Chikwana E, Davis B, Morakinyo MK, Simoyi RH. Oxyhalogen–sulfur chemistry — Kinetics and mechanism of oxidation of methionine by aqueous iodine and acidified iodate. CAN J CHEM 2009. [DOI: 10.1139/v09-038] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The oxidation of methionine (Met) by acidic iodate and aqueous iodine was studied. Though the reaction is a simple two-electron oxidation to give methionine sulfoxide (Met–S=O), the dynamics of the reaction are, however, very complex, characterized by clock reaction characteristics and transient formation of iodine. In excess methionine conditions, the stoichiometry of the reaction was deduced to be IO3– + 3Met → I– + 3Met–S=O. In excess iodate, the iodide product reacts with iodate to give a final product of molecular iodine and a 2:5 stoichiometry: 2IO3– + 5Met + 2H+→ I2 + 5Met–S=O + H2O. The direct reaction of iodine and methionine is slow and mildly autoinhibitory, which explains the transient formation of iodine, even in conditions of excess methionine in which iodine is not a final product. The whole reaction scheme could be simulated by a simple network of 11 reactions.
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Affiliation(s)
- Edward Chikwana
- Department of Chemistry, Portland State University, Portland, OR 97207-0751, USA
| | - Bradley Davis
- Department of Chemistry, Portland State University, Portland, OR 97207-0751, USA
| | - Moshood K. Morakinyo
- Department of Chemistry, Portland State University, Portland, OR 97207-0751, USA
| | - Reuben H. Simoyi
- Department of Chemistry, Portland State University, Portland, OR 97207-0751, USA
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23
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Kinetics and mechanism of oxidation of l-cystine by manganese(III) in sulfuric acid medium. TRANSIT METAL CHEM 2008. [DOI: 10.1007/s11243-008-9097-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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24
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Morakinyo MK, Chikwana E, Simoyi RH. Oxyhalogen–sulfur chemistry — Kinetics and mechanism of the bromate oxidation of cysteamine. CAN J CHEM 2008. [DOI: 10.1139/v08-031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The kinetics and mechanism of the oxidation of the biologically important molecule, cysteamine, by acidic bromate and molecular bromine have been studied. In excess acidic bromate conditions, cysteamine is oxidized to N-brominated derivatives, and in excess cysteamine the oxidation product is taurine according to the following stoichiometry: BrO3–+ H2NCH2CH2SH → H2NCH2CH2SO3H + Br–. There is quantitative formation of taurine before N-bromination commences. Excess aqueous bromine oxidizes cysteamine to give dibromotaurine: 5Br2+ H2NCH2CH2SH + 3H2O → Br2NCH2CH2SO3H + 8Br–+ 8H+, while excess cysteamine conditions gave monobromotaurine. The oxidation of cysteamine by aqueous bromine is effectively diffusion-controlled all the way to the formation of monobromotaurine. Further formation of dibromotaurine is dependent on acid concentrations, with highly acidic conditions inhibiting further reaction towards formation of dibromotaurine. The formation of the N-brominated derivatives of taurine is reversible, with taurine regenerated in the presence of a reducing agent such as iodide. This feature makes it possible for taurine to moderate hypobromous acid toxicity in the physiological environment.Key words: cysteamine, hypobromous acid, toxicities, antioxidant.
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25
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Wang X, Stanbury DM. Direct oxidation of L-cysteine by [FeIII(bpy)2(CN)2]+ and [FeIII(bpy)(CN)4]-. Inorg Chem 2008; 47:1224-36. [PMID: 18177037 DOI: 10.1021/ic701891m] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The oxidation of L-cysteine by the outer-sphere oxidants [Fe(bpy)2(CN)2]+ and [Fe(bpy)(CN)4]- in anaerobic aqueous solution is highly susceptible to catalysis by trace amounts of copper ions. This copper catalysis is effectively inhibited with the addition of 1.0 mM dipicolinic acid for the reduction of [Fe(bpy)2(CN)2]+ and is completely suppressed with the addition of 5.0 mM EDTA (pH<9.00), 10.0 mM EDTA (9.0<pH<or=10.0), and 1.0 mM cyclam (pH>10.0) for the reduction of [Fe(bpy)(CN)4]-. 1H NMR and UV-vis spectra show that the products of the direct (uncatalyzed) reactions are the corresponding Fe(II) complexes and, when no radical scavengers are present, L-cystine, both being formed quantitatively. The two reactions display mild kinetic inhibition by Fe(II), and the inhibition can be suppressed by the free radical scavenger PBN (N-tert-butyl-alpha-phenylnitrone). At 25 degrees C and micro=0.1 M and under conditions where inhibition by Fe(II) is insignificant, the general rate law is -d[Fe(III)]/dt=k[cysteine]tot[Fe(III)], with k={k2Ka1[H+]2+k3Ka1Ka2[H+]+k4Ka1Ka2Ka3{/}[H+]3+Ka1[H+]2+Ka1Ka2[H+]+Ka1Ka2Ka3}, where Ka1, Ka2, and Ka3 are the successive acid dissociation constants of HSCH2CH(NH3+)CO2H. For [Fe(bpy)2(CN)2]+, the kinetics over the pH range of 3-7.9 yields k2=3.4+/-0.6 M(-1) s(-1) and k3=(1.18+/-0.02)x10(6) M(-1) s(-1) (k4 is insignificant in the fitting). For [Fe(bpy)(CN)4]- over the pH range of 6.1-11.9, the rate constants are k3=(2.13+/-0.08)x10(3) M(-1) s(-1) and k4=(1.01+/-0.06)x10(4) M(-1) s(-1) (k2 is insignificant in the fitting). All three terms in the rate law are assigned to rate-limiting electron-transfer reactions in which various thiolate forms of cysteine are reactive. Applying Marcus theory, the self-exchange rate constant of the *SCH2CH(NH2)CO2-/-SCH2CH(NH2)CO2- redox couple was obtained from the oxidation of L-cysteine by [Fe(bpy)(CN)4]-, with k11=4x10(5) M(-1) s(-1). The self-exchange rate constant of the *SCH2CH(NH3+)CO2-/-SCH2CH(NH3+)CO2- redox couple was similarly obtained from the rates with both Fe(III) oxidants, a value of 6x10(6) M(-1) s(-1) for k11 being derived. Both self-exchange rate constants are quite large as is to be expected from the minimal rearrangement that follows conversion of a thiolate to a thiyl radical, and the somewhat lower self-exchange rate constant for the dianionic form of cysteine is ascribed to electrostatic repulsion.
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Affiliation(s)
- Xiaoguang Wang
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, USA
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26
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Maruyama T, Sonokawa S, Matsushita H, Goto M. Inhibitiory effects of gold(III) ions on ribonuclease and deoxyribonuclease. J Inorg Biochem 2007; 101:180-6. [PMID: 17084460 DOI: 10.1016/j.jinorgbio.2006.09.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2006] [Revised: 09/18/2006] [Accepted: 09/18/2006] [Indexed: 11/29/2022]
Abstract
Inhibitory effects of gold(III) ions (Au(III)) on ribonuclease A (RNase A) and deoxyribonuclease I (DNase I) were investigated at neutral pH. RNase A was completely inhibited by 3 molar equivalents of Au(III) ions. DNase I was inhibited by 10 molar equivalents of Au(III) ions. Stoichiometric analyses suggest that Au(III) ions were coordinated to RNase A molecules. The Au(III)-inhibited RNase A and DNase I were renatured to exhibit 80% and 60% of their intrinsic activity, when the bound Au(III) ions were eliminated from the nucleases by addition of thiourea, which forms a strong complex with gold ions. This suggests that RNase A and DNase I were not oxidized to lose their activity, but reversibly complexed with Au(III) ions to lose their activity. Au(III) ions were probably considered to be bound to histidine and methionine residues in the nucleases, resulting in the inhibition of their activity. CD spectra revealed that the Au(III)-induced inhibition caused a conformational change in RNase A molecules and that the addition of thiourea induced refolding of the Au(III)-inhibited RNase A.
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Affiliation(s)
- Tatsuo Maruyama
- Department of Applied Chemistry, Graduate School of Engineering and Center for Future Chemistry, Kyushu University, 744 Moto-oka, Fukuoka 819-0395, Japan.
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27
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Ison A, Odeh IN, Margerum DW. Kinetics and Mechanisms of Chlorine Dioxide and Chlorite Oxidations of Cysteine and Glutathione. Inorg Chem 2006; 45:8768-75. [PMID: 17029389 DOI: 10.1021/ic0609554] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chlorine dioxide oxidation of cysteine (CSH) is investigated under pseudo-first-order conditions (with excess CSH) in buffered aqueous solutions, p[H+] 2.7-9.5 at 25.0 degrees C. The rates of chlorine dioxide decay are first order in both ClO2 and CSH concentrations and increase rapidly as the pH increases. The proposed mechanism is an electron transfer from CS- to ClO2 (1.03 x 10(8) M(-1) s(-1)) with a subsequent rapid reaction of the CS* radical and a second ClO2 to form a cysteinyl-ClO2 adduct (CSOClO). This highly reactive adduct decays via two pathways. In acidic solutions, it hydrolyzes to give CSO(2)H (sulfinic acid) and HOCl, which in turn rapidly react to form CSO3H (cysteic acid) and Cl-. As the pH increases, the (CSOClO) adduct reacts with CS- by a second pathway to form cystine (CSSC) and chlorite ion (ClO2-). The reaction stoichiometry changes from 6 ClO2:5 CSH at low pH to 2 ClO2:10 CSH at high pH. The ClO2 oxidation of glutathione anion (GS-) is also rapid with a second-order rate constant of 1.40 x 10(8) M(-1) s(-1). The reaction of ClO2 with CSSC is 7 orders of magnitude slower than the corresponding reaction with cysteinyl anion (CS-) at pH 6.7. Chlorite ion reacts with CSH; however, at p[H+] 6.7, the observed rate of this reaction is slower than the ClO2/CSH reaction by 6 orders of magnitude. Chlorite ion oxidizes CSH while being reduced to HOCl, which in turn reacts rapidly with CSH to form Cl-. The reaction products are CSSC and CSO3H with a pH-dependent distribution similar to the ClO2/CSH system.
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Affiliation(s)
- Ana Ison
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
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Olagunju O, Siegel PD, Olojo R, Simoyi RH. Oxyhalogen−Sulfur Chemistry: Kinetics and Mechanism of Oxidation of N-Acetylthiourea by Chlorite and Chlorine Dioxide. J Phys Chem A 2006; 110:2396-410. [PMID: 16480299 DOI: 10.1021/jp055805d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The oxidation reactions of N-acetylthiourea (ACTU) by chlorite and chlorine dioxide were studied in slightly acidic media. The ACTU-ClO(2)(-) reaction has a complex dependence on acid with acid catalysis in pH > 2 followed by acid retardation in higher acid conditions. In excess chlorite conditions the reaction is characterized by a very short induction period followed by a sudden and rapid formation of chlorine dioxide and sulfate. In some ratios of oxidant to reductant mixtures, oligo-oscillatory formation of chlorine dioxide is observed. The stoichiometry of the reaction is 2:1, with a complete desulfurization of the ACTU thiocarbamide to produce the corresponding urea product: 2ClO(2)(-) + CH(3)CONH(NH(2))C=S + H(2)O --> CH(3)CONH(NH(2))C=O + SO(4)(2-) + 2Cl(-) + 2H(+) (A). The reaction of chlorine dioxide and ACTU is extremely rapid and autocatalytic. The stoichiometry of this reaction is 8ClO(2)(aq) + 5CH(3)CONH(NH(2))C=S + 9H(2)O --> 5CH(3)CONH(NH(2))C=O + 5SO(4)(2-) + 8Cl(-) + 18H(+) (B). The ACTU-ClO(2)(-) reaction shows a much stronger HOCl autocatalysis than that which has been observed with other oxychlorine-thiocarbamide reactions. The reaction of chlorine dioxide with ACTU involves the initial formation of an adduct which hydrolyses to eliminate an unstable oxychlorine intermediate HClO(2)(-) which then combines with another ClO(2) molecule to produce and accumulate ClO(2)(-). The oxidation of ACTU involves the successive oxidation of the sulfur center through the sulfenic and sulfinic acids. Oxidation of the sulfinic acid by chlorine dioxide proceeds directly to sulfate bypassing the sulfonic acid. Sulfonic acids are inert to further oxidation and are only oxidized to sulfate via an initial hydrolysis reaction to yield bisulfite, which is then rapidly oxidized. Chlorine dioxide production after the induction period is due to the reaction of the intermediate HOCl species with ClO(2)(-). Oligo-oscillatory behavior arises from the fact that reactions that form ClO(2) are comparable in magnitude to those that consume ClO(2), and hence the assertion of each set of reactions is based on availability of reagents that fuel them. A computer simulation study involving 30 elementary and composite reactions gave a good fit to the induction period observed in the formation of chlorine dioxide and in the autocatalytic consumption of ACTU in its oxidation by ClO(2).
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Affiliation(s)
- Olufunke Olagunju
- Department of Chemistry, Portland State University, Portland, Oregon 97207-0751, USA
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29
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Wei M, Shi Z, Evans DG, Duan X. Study on the intercalation and interlayer oxidation transformation of l-cysteine in a confined region of layered double hydroxides. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b517980g] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Chigwada TR, Simoyi RH. S-Oxygenation of Thiocarbamides II: Oxidation of Trimethylthiourea by Chlorite and Chlorine Dioxide. J Phys Chem A 2005; 109:1094-104. [PMID: 16833418 DOI: 10.1021/jp045650u] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The kinetics of the oxidation of a substituted thiourea, trimethylthiourea (TMTU), by chlorite have been studied in slightly acidic media. The reaction is much faster than the comparable oxidation of the unsubstituted thiourea by chlorite. The stoichiometry of the reaction was experimentally deduced to be 2ClO2- + Me2N(NHMe)C=S + H2O --> 2Cl- + Me2N(NHMe)C=O + SO4(2-) + 2H+. In excess chlorite conditions, chlorine dioxide is formed after a short induction period. The oxidation of TMTU occurs in two phases. It starts initially with S-oxygenation of the sulfur center to yield the sulfinic acid, which then reacts in the second phase predominantly through an initial hydrolysis to produce trimethylurea and the sulfoxylate anion. The sulfoxylate anion is a highly reducing species which is rapidly oxidized to sulfate. The sulfinic and sulfonic acids of TMTU exists in the form of zwitterionic species that are stable in acidic environments and rapidly decompose in basic environments. The rate of oxidation of the sulfonic acid is determined by its rate of hydrolysis, which is inhibited by acid. The direct reaction of chlorine dioxide and TMTU is autocatalytic and also inhibited by acid. It commences with the initial formation of an adduct of the radical chlorine dioxide species with the electron-rich sulfur center of the thiocarbamide followed by reaction of the adduct with another chlorine dioxide molecule and subsequent hydrolysis to yield chlorite and a sulfenic acid. The bimolecular rate constant for the reaction of chlorine dioxide and TMTU was experimentally determined as 16 +/- 3.0 M(-1) s(-1) at pH 1.00.
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Affiliation(s)
- Tabitha R Chigwada
- Department of Chemistry, Portland State University, Portland, Oregon 97207-0751, USA
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Chigwada TR, Chikwana E, Simoyi RH. S-Oxygenation of Thiocarbamides I: Oxidation of Phenylthiourea by Chlorite in Acidic Media. J Phys Chem A 2005; 109:1081-93. [PMID: 16833417 DOI: 10.1021/jp0458654] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The oxidation of 1-phenyl-2-thiourea (PTU) by chlorite was studied in aqueous acidic media. The reaction is extremely complex with reaction dynamics strongly influenced by the pH of reaction medium. In excess chlorite concentrations the reaction stoichiometry involves the complete desulfurization of PTU to yield a urea residue and sulfate: 2ClO2- + PhN(H)CSNH2 + H2O --> SO4(2-) + PhN(H)CONH2 + 2Cl- + 2H+. In excess PTU, mixtures of sulfinic and sulfonic acids are formed. The reaction was followed spectrophotometrically by observing the formation of chlorine dioxide which is formed from the reaction of the reactive intermediate HOCl and chlorite: 2ClO2- + HOCl + H+ --> 2ClO2(aq) + Cl- + H2O. The complexity of the ClO2- - PTU reaction arises from the fact that the reaction of ClO2 with PTU is slow enough to allow the accumulation of ClO2 in the presence of PTU. Hence the formation of ClO2 was observed to be oligooscillatory with transient formation of ClO2 even in conditions of excess oxidant. The reaction showed complex acid dependence with acid catalysis in pH conditions higher than pKa of HClO2 and acid retardation in pH conditions of less than 2.0. The rate of oxidation of PTU was given by -d[PTU]/dt = k1[ClO2-][PTU] + k2[HClO2][PTU] with the rate law: -d[PTU]/dt = [Cl(III)](T)[PTU]0/K(a1) + [H+] [k1K(a1) + k2[H+]]; where [Cl(III)]T is the sum of chlorite and chlorous acid and K(a1) is the acid dissociation constant for chlorous acid. The following bimolecular rate constants were evaluated; k1 = 31.5+/-2.3 M(-1) s(-1) and k2 = 114+/-7 M(-1) s(-1). The direct reaction of ClO2 with PTU was autocatalytic in low acid concentrations with a stoichiometric ratio of 8:5; 8ClO2 + 5PhN(H)CSNH2 + 9H2O --> 5SO4(2-) + 5PhN(H)CONH2 + 8Cl- + 18H+. The proposed mechanism implicates HOCl as a major intermediate whose autocatalytic production determined the observed global dynamics of the reaction. A comprehensive 29-reaction scheme is evoked to describe the complex reaction dynamics.
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Affiliation(s)
- Tabitha R Chigwada
- Department of Chemistry, Portland State University, Portland, Oregon 97207-0751, USA
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