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González-Jiménez M, García-Santos MP, Bermejo Tesón B, Fuentes de Arriba ÁL, Arenas Valgañón J, Calle E, Casado J. Kinetic study on the reaction of sodium nitrite with neurotransmitters secreted in the stomach. Sci Rep 2023; 13:15713. [PMID: 37735226 PMCID: PMC10514311 DOI: 10.1038/s41598-023-42759-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 09/14/2023] [Indexed: 09/23/2023] Open
Abstract
Nitroso-compounds are potentially mutagenic and carcinogenic compounds due to their ability to alkylate DNA bases. One of the most common sources of human exposure to nitroso-compounds is their formation in the acidic environment of the stomach by the reaction between electron-rich molecules present in the lumen and sodium nitrite ingested in the diet. To date, the formation of nitroso-compounds by the reaction of nitrite with food components has been investigated in depth, but little attention has been paid to substances secreted in the stomach, such as dopamine or serotonin, whose reaction products with nitrite have proven mutagenic properties. In this article, we present a kinetic study with UV-visible spectroscopy of the nitrosation reactions of both molecules, as well as of L-tyrosine, the amino-acid precursor of dopamine. We determined the kinetic parameters and reaction mechanisms for the reactions, studying the influence of the reactants concentration, pH, temperature, and ionic strength on the reaction rate. In all cases, the favoured reaction product was a stable nitroso-compound. Serotonin, the molecule whose product was the most mutagenic, underwent two consecutive nitrosation reactions. These findings suggest that additional biological research is needed to understand how this reaction alters the function of these neurotransmitters as well as the potentially toxic effects they may have once nitrosated.
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Affiliation(s)
- Mario González-Jiménez
- Departamento de Química Física, Universidad de Salamanca, Plaza de los Caídos, 1-5, 37008, Salamanca, Spain.
- School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - M Pilar García-Santos
- Departamento de Química Física, Universidad de Salamanca, Plaza de los Caídos, 1-5, 37008, Salamanca, Spain
| | - Blanca Bermejo Tesón
- Departamento de Química Física, Universidad de Salamanca, Plaza de los Caídos, 1-5, 37008, Salamanca, Spain
| | - Ángel L Fuentes de Arriba
- Departamento de Química Orgánica, Universidad de Salamanca, Plaza de los Caídos, 1-5, 37008, Salamanca, Spain
| | - Jorge Arenas Valgañón
- Departamento de Química Física, Universidad de Salamanca, Plaza de los Caídos, 1-5, 37008, Salamanca, Spain
| | - Emilio Calle
- Departamento de Química Física, Universidad de Salamanca, Plaza de los Caídos, 1-5, 37008, Salamanca, Spain
| | - Julio Casado
- Departamento de Química Física, Universidad de Salamanca, Plaza de los Caídos, 1-5, 37008, Salamanca, Spain
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2
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Tsao N, Schärer OD, Mosammaparast N. The complexity and regulation of repair of alkylation damage to nucleic acids. Crit Rev Biochem Mol Biol 2021; 56:125-136. [PMID: 33430640 DOI: 10.1080/10409238.2020.1869173] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
DNA damaging agents have been a cornerstone of cancer therapy for nearly a century. The discovery of many of these chemicals, particularly the alkylating agents, are deeply entwined with the development of poisonous materials originally intended for use in warfare. Over the last decades, their anti-proliferative effects have focused on the specific mechanisms by which they damage DNA, and the factors involved in the repair of such damage. Due to the variety of aberrant adducts created even for the simplest alkylating agents, numerous pathways of repair are engaged as a defense against this damage. More recent work has underscored the role of RNA damage in the cellular response to these agents, although the understanding of their role in relation to established DNA repair pathways is still in its infancy. In this review, we discuss the chemistry of alkylating agents, the numerous ways in which they damage nucleic acids, as well as the specific DNA and RNA repair pathways which are engaged to counter their effects.
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Affiliation(s)
- Ning Tsao
- Department of Pathology and Immunology, Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO, USA
| | - Orlando D Schärer
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Republic of Korea.,Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Nima Mosammaparast
- Department of Pathology and Immunology, Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO, USA
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3
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Abstract
Similar to many other biological molecules, RNA is vulnerable to chemical insults from endogenous and exogenous sources. Noxious agents such as reactive oxygen species or alkylating chemicals have the potential to profoundly affect the chemical properties and hence the function of RNA molecules in the cell. Given the central role of RNA in many fundamental biological processes, including translation and splicing, changes to its chemical composition can have a detrimental impact on cellular fitness, with some evidence suggesting that RNA damage has roles in diseases such as neurodegenerative disorders. We are only just beginning to learn about how cells cope with RNA damage, with recent studies revealing the existence of quality-control processes that are capable of recognizing and degrading or repairing damaged RNA. Here, we begin by reviewing the most abundant types of chemical damage to RNA, including oxidation and alkylation. Focusing on mRNA damage, we then discuss how alterations to this species of RNA affect its function and how cells respond to these challenges to maintain proteostasis. Finally, we briefly discuss how chemical damage to noncoding RNAs such as rRNA, tRNA, small nuclear RNA, and small nucleolar RNA is likely to affect their function.
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Affiliation(s)
- Liewei L. Yan
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130
| | - Hani S. Zaher
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130, To whom correspondence should be addressed:
Dept. of Biology, Washington University in St. Louis, Campus Box 1137, One Brookings Dr., St. Louis, MO 63130. Tel.:
314-935-7662; Fax:
314-935-4432; E-mail:
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4
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Potjewyd G, Day PJ, Shangula S, Margison GP, Povey AC. L-β-N-methylamino-l-alanine (BMAA) nitrosation generates a cytotoxic DNA damaging alkylating agent: An unexplored mechanism for neurodegenerative disease. Neurotoxicology 2017; 59:105-109. [PMID: 28163087 DOI: 10.1016/j.neuro.2017.01.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 01/26/2017] [Accepted: 01/26/2017] [Indexed: 10/20/2022]
Abstract
BACKGROUND L-β-N-methylamino-l-alanine (BMAA) is a non-proteinic amino acid, that is neurotoxic in vitro and in animals, and is implicated in the causation of amyotrophic lateral sclerosis and parkinsonism-dementia complex (ALS-PDC) on Guam. Given that natural amino acids can be N-nitrosated to form toxic alkylating agents and the structural similarity of BMAA to other amino acids, our hypothesis was that N-nitrosation of BMAA might result in a toxic alkylating agent, providing a novel mechanistic hypothesis for BMAA action. FINDINGS We have chemically nitrosated BMAA with sodium nitrite to produce nitrosated BMAA (N-BMAA) which was shown to react with the alkyl-trapping agent, 4-(p-nitrobenzyl)pyridine, cause DNA strand breaks in vitro and was toxic to the human neuroblastoma cell line SH-SY5Y under conditions in which BMAA itself was minimally toxic. CONCLUSIONS Our results indicate that N-BMAA is an alkylating agent and toxin suggesting a plausible and previously unrecognised mechanism for the neurotoxic effects of BMAA.
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Affiliation(s)
- G Potjewyd
- Centre for Epidemiology, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - P J Day
- Centre for Epidemiology, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK; Manchester Institute for Biotechnology, University of Manchester, Manchester, UK
| | - S Shangula
- Centre for Epidemiology, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - G P Margison
- Centre for Epidemiology, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - A C Povey
- Centre for Epidemiology, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
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5
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Trost BM, Knopf JD, Brindle CS. Synthetic Strategies Employed for the Construction of Fostriecin and Related Natural Products. Chem Rev 2016; 116:15035-15088. [PMID: 28027648 PMCID: PMC5720176 DOI: 10.1021/acs.chemrev.6b00488] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Fostriecin and related natural products present a significant challenge for synthetic chemists due to their structural complexity and chemical sensitivity. This review will chronicle the successful efforts of synthetic chemists in the construction of these biologically active molecules. Key carbon-carbon bond forming reactions will be highlighted, as well as the methods used to install the numerous stereocenters present in this class of compounds.
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Affiliation(s)
- Barry M. Trost
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States
| | - Joshua D. Knopf
- Department of Chemistry, Trinity College, 300 Summit Street, Hartford, Connecticut 06106, United States
| | - Cheyenne S. Brindle
- Department of Chemistry, Trinity College, 300 Summit Street, Hartford, Connecticut 06106, United States
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6
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Ulusoy S, Ulusoy HI, Pleissner D, Eriksen NT. Nitrosation and analysis of amino acid derivatives by isocratic HPLC. RSC Adv 2016. [DOI: 10.1039/c5ra25854e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Amino acids are transformed by nitrosation with dinitrogen trioxide into their corresponding α-hydroxy acids, which are separated and analysed by HPLC, and used to quantify the original amino acid concentration in samples.
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Affiliation(s)
- Songül Ulusoy
- Department of Chemistry and Bioscience
- Aalborg University
- DK-9220 Aalborg
- Denmark
- Department of Chemistry
| | - Halil Ibrahim Ulusoy
- Department of Chemistry and Bioscience
- Aalborg University
- DK-9220 Aalborg
- Denmark
- Department of Analytical Chemistry
| | - Daniel Pleissner
- Department of Bioengineering
- Leibniz-Institute for Agricultural Engineering Potsdam-Bornim e. V
- Potsdam
- Germany
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7
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Rathod KS, Velmurugan S, Ahluwalia A. A 'green' diet-based approach to cardiovascular health? Is inorganic nitrate the answer? Mol Nutr Food Res 2015; 60:185-202. [PMID: 26256112 DOI: 10.1002/mnfr.201500313] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/16/2015] [Accepted: 07/10/2015] [Indexed: 12/22/2022]
Abstract
Ingestion of fruit and vegetables rich in inorganic nitrate (NO(3)(-)) has emerged as an effective method for acutely elevating vascular nitric oxide (NO) levels through formation of an NO(2)(-) intermediate. As such a number of beneficial effects of NO(3)(-) and NO(2)(-) ingestion have been demonstrated including reductions in blood pressure, measures of arterial stiffness and platelet activity. The pathway for NO generation from such dietary interventions involves the activity of facultative oral microflora that facilitate the reduction of inorganic NO(3)(-), ingested in the diet, to inorganic NO(2)(-). This NO(2)(-) then eventually enters the circulation where, through the activity of one or more of a range of distinct NO(2)(-) reductases, it is chemically reduced to NO. This pathway provides an alternative route for in vivo NO generation that could be utilized for therapeutic benefit in those cardiovascular disease states where reduced bioavailable NO is thought to contribute to pathogenesis. Indeed, the cardiovascular benefits of NO(2)(-) and NO(3)(-) are now starting to be translated in patients in several clinical trials. In this review, we discuss recent evidence supporting the potential utility of delivery of NO(3)(-) or NO(2)(-) for the treatment of cardiovascular diseases.
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Affiliation(s)
- Krishnaraj Sinhji Rathod
- William Harvey Research Institute, Barts NIHR Cardiovascular Biomedical Research Unit, Barts & The London Medical School, Queen Mary University of London, Charterhouse Square, London, UK
| | - Shanti Velmurugan
- William Harvey Research Institute, Barts NIHR Cardiovascular Biomedical Research Unit, Barts & The London Medical School, Queen Mary University of London, Charterhouse Square, London, UK
| | - Amrita Ahluwalia
- William Harvey Research Institute, Barts NIHR Cardiovascular Biomedical Research Unit, Barts & The London Medical School, Queen Mary University of London, Charterhouse Square, London, UK
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8
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Mielecki D, Wrzesiński M, Grzesiuk E. Inducible repair of alkylated DNA in microorganisms. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2014; 763:294-305. [PMID: 25795127 DOI: 10.1016/j.mrrev.2014.12.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 12/01/2014] [Accepted: 12/02/2014] [Indexed: 12/15/2022]
Abstract
Alkylating agents, which are widespread in the environment, also occur endogenously as primary and secondary metabolites. Such compounds have intrinsically extremely cytotoxic and frequently mutagenic effects, to which organisms have developed resistance by evolving multiple repair mechanisms to protect cellular DNA. One such defense against alkylation lesions is an inducible Adaptive (Ada) response. In Escherichia coli, the Ada response enhances cell resistance by the biosynthesis of four proteins: Ada, AlkA, AlkB, and AidB. The glycosidic bonds of the most cytotoxic lesion, N3-methyladenine (3meA), together with N3-methylguanine (3meG), O(2)-methylthymine (O(2)-meT), and O(2)-methylcytosine (O(2)-meC), are cleaved by AlkA DNA glycosylase. Lesions such as N1-methyladenine (1meA) and N3-methylcytosine (3meC) are removed from DNA and RNA by AlkB dioxygenase. Cytotoxic and mutagenic O(6)-methylguanine (O(6)meG) is repaired by Ada DNA methyltransferase, which transfers the methyl group onto its own cysteine residue from the methylated oxygen. We review (i) the individual Ada proteins Ada, AlkA, AlkB, AidB, and COG3826, with emphasis on the ubiquitous and versatile AlkB and its prokaryotic and eukaryotic homologs; (ii) the organization of the Ada regulon in several bacterial species; (iii) the mechanisms underlying activation of Ada transcription. In vivo and in silico analysis of various microorganisms shows the widespread existence and versatile organization of Ada regulon genes, including not only ada, alkA, alkB, and aidB but also COG3826, alkD, and other genes whose roles in repair of alkylated DNA remain to be elucidated. This review explores the comparative organization of Ada response and protein functions among bacterial species beyond the classical E. coli model.
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Affiliation(s)
- Damian Mielecki
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5A, 02-106 Warszawa, Poland
| | - Michał Wrzesiński
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5A, 02-106 Warszawa, Poland
| | - Elżbieta Grzesiuk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5A, 02-106 Warszawa, Poland.
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9
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Yang ZJ, Liu CZ, Hu BL, Deng CL, Zhang XG. Oxidative tandem nitrosation/cyclization of N-aryl enamines with nitromethane toward 3-(trifluoromethyl)quinoxalines. Chem Commun (Camb) 2014; 50:14554-7. [DOI: 10.1039/c4cc07083f] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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10
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Dürüst Y, Sağırlı A. Microwave-Assisted Coupling Reaction of N-Aryl Sydnones with 2-Nitromethylenethiazolidine: Unexpected Formation of (Z)-2-(Nitro((E)-p-substitutedphenyldiazenyl)methylene)thiazolidines. J Org Chem 2014; 79:6380-4. [PMID: 24901714 DOI: 10.1021/jo5010229] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yaşar Dürüst
- Department
of Chemistry, Abant İzzet Baysal University, TR-14280, Bolu, Turkey
| | - Akın Sağırlı
- Department
of Chemistry, Abant İzzet Baysal University, TR-14280, Bolu, Turkey
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11
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Zhang F, Tsunoda M, Kikuchi Y, Wilkinson O, Millington CL, Margison GP, Williams DM, Takénaka A. O6-Carboxymethylguanine in DNA forms a sequence context-dependent wobble base-pair structure with thymine. ACTA ACUST UNITED AC 2014; 70:1669-79. [DOI: 10.1107/s1399004714006178] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 03/19/2014] [Indexed: 11/10/2022]
Abstract
N-Nitrosation of glycine and its derivatives generates potent alkylating agents that can lead to the formation ofO6-carboxymethylguanine (O6-CMG) in DNA.O6-CMG has been identified in DNA derived from human colon tissue and its occurrence has been linked to diets high in red and processed meats, implying an association with the induction of colorectal cancer. By analogy toO6-methylguanine,O6-CMG is expected to be mutagenic, inducing G-to-A mutations that may be the molecular basis of increased cancer risk. Previously, the crystal structure of the DNA dodecamer d(CGCG[O6-CMG]ATTCGCG) has been reported, in whichO6-CMG forms a Watson–Crick-type pair with thymine similar to the canonical A:T pair. In order to further investigate the versatility ofO6-CMG in base-pair formation, the structure of the DNA dodecamer d(CGC[O6-CMG]AATTTGCG) containingO6-CMG at a different position has been determined by X-ray crystallography using four crystal forms obtained under conditions containing different solvent ions (Sr2+, Ba2+, Mg2+, K+or Na+) with and without Hoechst 33258. The most striking finding is that the pairing modes ofO6-CMG with T are quite different from those previously reported. In the present dodecamer, the T bases are displaced (wobbled) into the major groove to form a hydrogen bond between the thymine N3N—H and the carboxyl group ofO6-CMG. In addition, a water molecule is bridged through two hydrogen bonds between the thymine O2atom and the 2-amino group ofO6-CMG to stabilize the pairing. These interaction modes commonly occur in the four crystal forms, regardless of the differences in crystallization conditions. The previous and the present results show thatO6-CMG can form a base pair with T in two alternative modes: the Watson–Crick type and a high-wobble type, the nature of which may depend on the DNA-sequence context.
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12
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Zhang F, Tsunoda M, Suzuki K, Kikuchi Y, Wilkinson O, Millington CL, Margison GP, Williams DM, Czarina Morishita E, Takénaka A. Structures of DNA duplexes containing O6-carboxymethylguanine, a lesion associated with gastrointestinal cancer, reveal a mechanism for inducing pyrimidine transition mutations. Nucleic Acids Res 2013; 41:5524-32. [PMID: 23580550 PMCID: PMC3664797 DOI: 10.1093/nar/gkt198] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
N-nitrosation of glycine and its derivatives generates potent alkylating agents that can lead to the formation of O(6)-carboxymethylguanine (O(6)-CMG) in DNA. O(6)-CMG has been identified in DNA derived from human colon tissue, and its occurrence has been linked to diets high in red and processed meats. By analogy to O(6)-methylguanine, O(6)-CMG is expected to be highly mutagenic, inducing G to A mutations during DNA replication that can increase the risk of gastrointestinal and other cancers. Two crystal structures of DNA dodecamers d(CGCG[O(6)-CMG]ATTCGCG) and d(CGC[O(6)-CMG]AATTCGCG) in complex with Hoechst33258 reveal that each can form a self-complementary duplex to retain the B-form conformation. Electron density maps clearly show that O(6)-CMG forms a Watson-Crick-type pair with thymine similar to the canonical A:T pair, and it forms a reversed wobble pair with cytosine. In situ structural modeling suggests that a DNA polymerase can accept the Watson-Crick-type pair of O(6)-CMG with thymine, but might also accept the reversed wobble pair of O(6)-CMG with cytosine. Thus, O(6)-CMG would permit the mis-incorporation of dTTP during DNA replication. Alternatively, the triphosphate that would be formed by carboxymethylation of the nucleotide triphosphate pool d[O(6)-CMG]TP might compete with dATP incorporation opposite thymine in a DNA template.
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Affiliation(s)
- Fang Zhang
- Graduate School of Science and Engineering, Iwaki-Meisei University, Iwaki 970-8551, Japan
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13
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Arenas-Valgañón J, Gómez-Bombarelli R, González-Pérez M, González-Jiménez M, Calle E, Casado J. Taurine–nitrite interaction as a precursor of alkylation mechanisms. Food Chem 2012; 134:986-91. [DOI: 10.1016/j.foodchem.2012.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 01/24/2012] [Accepted: 03/01/2012] [Indexed: 11/25/2022]
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14
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Gómez-Bombarelli R, González-Pérez M, Calle E, Casado J. Potential of the NBP Method for the Study of Alkylation Mechanisms: NBP as a DNA-Model. Chem Res Toxicol 2012; 25:1176-91. [DOI: 10.1021/tx300065v] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rafael Gómez-Bombarelli
- Departamento de Química Física, Facultad de
Ciencias Químicas, Universidad de Salamanca, Plaza de los Caídos, 1-5, E-37008 Salamanca, Spain
| | - Marina González-Pérez
- Departamento de Química Física, Facultad de
Ciencias Químicas, Universidad de Salamanca, Plaza de los Caídos, 1-5, E-37008 Salamanca, Spain
| | - Emilio Calle
- Departamento de Química Física, Facultad de
Ciencias Químicas, Universidad de Salamanca, Plaza de los Caídos, 1-5, E-37008 Salamanca, Spain
| | - Julio Casado
- Departamento de Química Física, Facultad de
Ciencias Químicas, Universidad de Salamanca, Plaza de los Caídos, 1-5, E-37008 Salamanca, Spain
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15
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16
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Santra S, Perez JM. Selective N-alkylation of β-alanine facilitates the synthesis of a poly(amino acid)-based theranostic nanoagent. Biomacromolecules 2011; 12:3917-27. [PMID: 21961886 PMCID: PMC3215834 DOI: 10.1021/bm2009334] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The development of functional amino acid-based polymeric materials is emerging as a platform to create biodegradable and nontoxic nanomaterials for medical and biotechnology applications. In particular, facile synthetic routes for these polymers and their corresponding polymeric nanomaterials would have a positive impact in the development of novel biomaterials and nanoparticles. However, progress has been hampered by the need to use complex protection-deprotection methods and toxic phase transfer catalysts. In this study, we report a facile, single-step approach for the synthesis of an N-alkylated amino acid as an AB-type functional monomer to generate a novel pseudo-poly(amino acid), without using the laborious multistep, protection-deprotection methods. This synthetic strategy is reproducible, easy to scale up, and does not produce toxic byproducts. In addition, the synthesized amino acid-based polymer is different from conventional linear polymers as the butyl pendants enhance its solubility in common organic solvents and facilitate the creation of hydrophobic nanocavities for the effective encapsulation of hydrophobic cargos upon nanoparticle formation. Within the nanoparticles, we have encapsulated a hydrophobic DiI dye and a therapeutic drug, Taxol. In addition, we have conjugated folic acid as a folate receptor-targeting ligand for the targeted delivery of the nanoparticles to cancer cells expressing the folate receptor. Cell cytotoxicity studies confirm the low toxicity of the polymeric nanoparticles, and drug-release experiments with the Taxol-encapsulated nanoparticles only exhibit cytotoxicity upon internalization into cancer cells expressing the folate receptor. Taken together, these results suggested that our synthetic strategy can be useful for the one-step synthesis of amino acid-based small molecules, biopolymers, and theranostic polymeric nanoagents for the targeted detection and treatment of cancer.
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Affiliation(s)
- Santimukul Santra
- NanoScience Technology Center, College of Medicine, Chemistry Department, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, Florida 32826. USA
| | - J. Manuel Perez
- NanoScience Technology Center, College of Medicine, Chemistry Department, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, Florida 32826. USA
- Burnett School of Biomedical Sciences, College of Medicine, Chemistry Department, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, Florida 32826. USA
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17
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González-Jiménez M, Arenas-Valgañón J, Calle E, Casado J. Aromatic C-nitrosation of a bioactive molecule. Nitrosation of minoxidil. Org Biomol Chem 2011; 9:7680-4. [PMID: 21779549 DOI: 10.1039/c1ob05686g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Minoxidil (2,4-diamino-6-(piperidin-1'-yl)pyrimidine N(3)-oxide; CASRN 38304-91-5) is a bioactive molecule with several nitrosatable groups widely used as an antihypertensive and antialopecia agent. Here the nitrosation of minoxidil was investigated. The conclusions drawn are as follows: (i) In the pH = 2.3-5.0 range, the minoxidil molecule undergoes aromatic C-nitrosation by nitrite. The dominant reaction was C-5 nitrosation through a mechanism that appears to consist of an electrophilic attack on the nitrosatable substrate by H(2)NO(2)(+)/NO(+), followed by a slow proton transfer; (ii) the reactivity of minoxidil as a C-nitrosatable substrate proved to be 7-fold greater than that of phenol, this being attributed to the preferred para- and ortho-orientations of the two -NH(2) groups at positions 2 and 4 of the minoxidil molecule, which activate electrophilic substitution in the C-5 position through their mesomeric effect. The N-nitrosominoxidil resulting from the nitrosation could be potentially harmful to the minoxidil users.
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18
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Manso JA, Camacho IFC, Calle E, Casado J. Alkylating potential of α,β-unsaturated compounds. Org Biomol Chem 2011; 9:6226-33. [PMID: 21773622 DOI: 10.1039/c1ob05298e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Alkylation reactions of the nucleoside guanosine (Guo) by the α,β-unsaturated compounds (α,β-UC) acrylonitrile (AN), acrylamide (AM), acrylic acid (AA) and acrolein (AC), which can act as alkylating agents of DNA, were investigated kinetically. The following conclusions were drawn: i) The Guo alkylation mechanism by AC is different from those brought about the other α,β-UC; ii) for the first three, the following sequence of alkylating potential was found: AN > AM > AA; iii) A correlation between the chemical reactivity (alkylation rate constants) of AN, AM, and AA and their capacity to form adducts with biomarkers was found. iv) Guo alkylation reactions for AN and AM occur through Michael addition mechanisms, reversible in the first case, and irreversible in the second. The equilibrium constant for the formation of the Guo-AN adduct is K(eq) (37 °C) = 5 × 10(-4); v) The low energy barrier (≈10 kJ mol(-1)) to reverse the Guo alkylation by AN reflects the easy reversibility of this reaction and its possible correction by repair mechanisms; vi) No reaction was observed for AN, AM, and AA at pH < 8.0. In contrast, Guo alkylation by AC was observed under cellular pH conditions. The reaction rate constants for the formation of the α-OH-Guo adduct (the most genotoxic isomer), is 1.5-fold faster than that of γ-OH-Guo. vii) a correlation between the chemical reactivity of α,β-UC (alkylation rate constants) and mutagenicity was found.
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Affiliation(s)
- José A Manso
- Departamento de Química Física, Universidad de Salamanca, Salamanca, Spain
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Pleissner D, Wimmer R, Eriksen NT. Quantification of Amino Acids in Fermentation Media by Isocratic HPLC Analysis of Their α-Hydroxy Acid Derivatives. Anal Chem 2010; 83:175-81. [DOI: 10.1021/ac1021908] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Daniel Pleissner
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmsvej 49, DK-9000 Aalborg, and Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Reinhard Wimmer
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmsvej 49, DK-9000 Aalborg, and Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Niels T. Eriksen
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmsvej 49, DK-9000 Aalborg, and Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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Pérez-Prior MT, Gómez-Bombarelli R, González-Pérez M, Manso JA, García-Santos MP, Calle E, Casado J. Sorbate−Nitrite Interactions: Acetonitrile Oxide as an Alkylating Agent. Chem Res Toxicol 2009; 22:1320-4. [DOI: 10.1021/tx9001226] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | - José A. Manso
- Departamento de Química Física, Universidad de Salamanca, E-37008 Salamanca, Spain
| | | | - Emilio Calle
- Departamento de Química Física, Universidad de Salamanca, E-37008 Salamanca, Spain
| | - Julio Casado
- Departamento de Química Física, Universidad de Salamanca, E-37008 Salamanca, Spain
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Manso JA, Pérez-Prior MT, Gómez-Bombarelli R, González-Pérez M, Céspedes IF, García-Santos MP, Calle E, Casado J. Alkylating potential ofN-phenyl-N-nitrosourea. J PHYS ORG CHEM 2009. [DOI: 10.1002/poc.1456] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Manso JA, Pérez-Prior MT, García-Santos MP, Calle E, Casado J. Steric effect in alkylation reactions byN-alkyl-N-nitrosoureas: a kinetic approach. J PHYS ORG CHEM 2008. [DOI: 10.1002/poc.1402] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Gómez-Bombarelli R, González-Pérez M, Pérez-Prior MT, Manso JA, Calle E, Casado J. Chemical Reactivity and Biological Activity of Diketene. Chem Res Toxicol 2008; 21:1964-9. [DOI: 10.1021/tx800153j] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | - José A. Manso
- Departamento de Química física, Universidad de Salamanca, E-37008 Salamanca, Spain
| | - Emilio Calle
- Departamento de Química física, Universidad de Salamanca, E-37008 Salamanca, Spain
| | - Julio Casado
- Departamento de Química física, Universidad de Salamanca, E-37008 Salamanca, Spain
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Manso JA, Pérez-Prior MT, del Pilar García-Santos M, Calle E, Casado J. Solvent Effects on the Enthalpy and Entropy of Activation for the Hydrolysis of β-Lactones. J SOLUTION CHEM 2008. [DOI: 10.1007/s10953-008-9250-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Fernández-Rodríguez E, Manso JA, Pérez-Prior MT, García-Santos MDP, Calle E, Casado J. The unusual ability of α-angelicalactone to form adducts: A kinetic approach. INT J CHEM KINET 2007. [DOI: 10.1002/kin.20273] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Pérez-Prior MT, Manso JA, García-Santos MDP, Calle E, Casado J. Alkylating potential of potassium sorbate. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2005; 53:10244-7. [PMID: 16366722 DOI: 10.1021/jf052152p] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A kinetic study of the alkylating potential of potassium sorbate (S)-a food preservative used worldwide-in 7:3 water/dioxane medium was performed. The following conclusions were drawn: (i) Potassium sorbate shows alkylating activity on the nucleophile 4-(p-nitrobenzyl)pyridine (NBP), a trap for alkylating agents with nucleophilic characteristics similar to those of DNA bases, (ii) The NBP alkylation reaction complies with the rate equation r = k(alk)[H+][S][NBP]/(K(a) + [H+]), K(a) being the sorbic acid dissociation constant and k(alk) the rate constant of NBP alkylation by the undissociated acid. In the range of pH 5-6, the alkylation time ranges between 18 days (pH 5.2) and >1 month (pH > or = 6). (iii) NBP alkylation occurs through a reaction with deltaH# = 78 kJ mol(-1), which is much higher than those of NBP alkylation by stronger alkylating agents. (iv) The absorption coefficient of the sorbate-NBP adduct was determined to be epsilon = 204 M(-1) cm(-1) (lambda = 580 nm), this value being rationalized in terms of the adduct structure. (v) The results can help to establish suitable expiration times for products preserved with potassium sorbate.
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Affiliation(s)
- M Teresa Pérez-Prior
- Departamento de Química física, Universidad de Salamanca, E-37008 Salamanca, Spain
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Manso JA, Pérez-Prior MT, García-Santos MDP, Calle E, Casado J. A Kinetic Approach to the Alkylating Potential of Carcinogenic Lactones. Chem Res Toxicol 2005; 18:1161-6. [PMID: 16022509 DOI: 10.1021/tx050031d] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The alkylating potential of beta-propiolactone (BPL), beta-butyrolactone (BBL), gamma-butyrolactone, and delta-valerolactone, which can be formed by the in vivo nitrosation of primary amino acids, was investigated kinetically. The nucleophile NBP, 4-(p-nitrobenzyl)pyridine, a trap for alkylating agents, was used as an alkylation substrate. The alkylation reactions were performed under mimicked cellular conditions at neutral pH in water/dioxane solvent mixtures. To gain insight into the effect of the hydrolysis of lactones on their alkylating efficiency, alkylation and competing hydrolysis were studied in parallel. Conclusions were drawn as follows: (i) gamma-Butyrolactone and delta-valerolactone afford neither appreciable NBP alkylation nor hydrolysis reactions; (ii) the alkylating potential of BPL is 10-fold higher than that of BBL, the reactivity of both being essentially enthalpy-controlled; (iii) a correlation was found between the alkylating potential of lactones and their carcinogenicity; (iv) the hydrolysis of lactones is not sufficiently effective to prevent alkylation; (v) the efficiency of alkylation, expressed as the alkylation rate/hydrolysis rate ratio, decreases strongly with increasing amounts of dioxane in the reaction media; (vi) the absorption coefficients of the NBP-lactone adducts are as follows: epsilon(NBP-BPL) = 5101 +/- 111 M(-1) cm(-1) (lambda = 584 nm) and epsilon(NBP-BBL) = 462 +/- 19 M(-1) cm(-1) (lambda = 586 nm), the pronounced difference between these values being rationalized in terms of the adducts' structure; and (vii) linear correlations exist between the adducts' absorption coefficients and the water/dioxane ratio in the reaction media.
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Affiliation(s)
- José A Manso
- Departamento de Química física, Universidad de Salamanca, E-37008 Salamanca, Spain
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Drabløs F, Feyzi E, Aas PA, Vaagbø CB, Kavli B, Bratlie MS, Peña-Diaz J, Otterlei M, Slupphaug G, Krokan HE. Alkylation damage in DNA and RNA--repair mechanisms and medical significance. DNA Repair (Amst) 2005; 3:1389-407. [PMID: 15380096 DOI: 10.1016/j.dnarep.2004.05.004] [Citation(s) in RCA: 443] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2004] [Indexed: 12/13/2022]
Abstract
Alkylation lesions in DNA and RNA result from endogenous compounds, environmental agents and alkylating drugs. Simple methylating agents, e.g. methylnitrosourea, tobacco-specific nitrosamines and drugs like temozolomide or streptozotocin, form adducts at N- and O-atoms in DNA bases. These lesions are mainly repaired by direct base repair, base excision repair, and to some extent by nucleotide excision repair (NER). The identified carcinogenicity of O(6)-methylguanine (O(6)-meG) is largely caused by its miscoding properties. Mutations from this lesion are prevented by O(6)-alkylG-DNA alkyltransferase (MGMT or AGT) that repairs the base in one step. However, the genotoxicity and cytotoxicity of O(6)-meG is mainly due to recognition of O(6)-meG/T (or C) mispairs by the mismatch repair system (MMR) and induction of futile repair cycles, eventually resulting in cytotoxic double-strand breaks. Therefore, inactivation of the MMR system in an AGT-defective background causes resistance to the killing effects of O(6)-alkylating agents, but not to the mutagenic effect. Bifunctional alkylating agents, such as chlorambucil or carmustine (BCNU), are commonly used anti-cancer drugs. DNA lesions caused by these agents are complex and require complex repair mechanisms. Thus, primary chloroethyl adducts at O(6)-G are repaired by AGT, while the secondary highly cytotoxic interstrand cross-links (ICLs) require nucleotide excision repair factors (e.g. XPF-ERCC1) for incision and homologous recombination to complete repair. Recently, Escherichia coli protein AlkB and human homologues were shown to be oxidative demethylases that repair cytotoxic 1-methyladenine (1-meA) and 3-methylcytosine (3-meC) residues. Numerous AlkB homologues are found in viruses, bacteria and eukaryotes, including eight human homologues (hABH1-8). These have distinct locations in subcellular compartments and their functions are only starting to become understood. Surprisingly, AlkB and hABH3 also repair RNA. An evaluation of the biological effects of environmental mutagens, as well as understanding the mechanism of action and resistance to alkylating drugs require a detailed understanding of DNA repair processes.
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Affiliation(s)
- Finn Drabløs
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, N-7489 Trondheim, Norway
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Pérez-Prior MT, Manso JA, del Pilar García-Santos M, Calle E, Casado J. Reactivity of Lactones and GHB Formation. J Org Chem 2004; 70:420-6. [PMID: 15651781 DOI: 10.1021/jo040271i] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The behavior of lactones in their hydrolysis reactions is a good indicator of their reactivity as electrophilic molecules. The hydrolysis of four- to six-membered lactones was investigated in neutral (water) and slightly acid media and in water/dioxane media. The following conclusions were drawn: (i) The reactivity of beta-propiolactone in neutral water is more than four times greater than that of beta-butyrolactone, due to the flow of charge caused by the latter's methyl substituent. Reactivity is enthalpy-controlled. (ii) The reactivity of beta-lactones diminishes in water/dioxane media when the percentage of dioxane increases. The increase in the dioxane percentage relaxing the intermolecular hydrogen bonds in the ordered structure of the water reduces DeltaH# and simultaneously increases the -DeltaS# value. (iii) An inverse solvent kinetic isotope effect in the acid-catalyzed hydrolysis of gamma-butyrolactone and delta-valerolactone was observed, this being indicative of acyl cleavage. (iv) The DeltaH# and DeltaS# values permit discrimination between alkyl and acyl cleavage. (v) A correlation was found between the chemical reactivity of lactones and their carcinogenic activity. (vi) The results suggest that orally ingested gamma-butyrolactone remains largely in its nonhydrolyzed form in the stomach before passing into the blood. (vii) The concentration equilibrium constant of GHB formation at human body temperature is Keq (37 degrees C)=0.40. (viii) Study of GHB formation shows that, contrary to earlier results, this is an endothermic process, with DeltarH=3.6 kJ mol(-1).
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Affiliation(s)
- M Teresa Pérez-Prior
- Departamento de Química Física, Universidad de Salamanca, E-37008 Salamanca, Spain
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González-Mancebo S, Gaspar J, Calle E, Pereira S, Mariano A, Rueff J, Casado J. Stereochemical effects in the metabolic activation of nitrosopiperidines: correlations with genotoxicity. Mutat Res 2004; 558:45-51. [PMID: 15036118 DOI: 10.1016/j.mrgentox.2003.10.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2003] [Revised: 10/17/2003] [Accepted: 10/28/2003] [Indexed: 11/26/2022]
Abstract
The genotoxicity of nitrosopiperidine and six alkyl derivatives was studied by use of the Ames tester strains TA100 and TA1535 in the pre-incubation method. Among the compounds investigated, those exhibiting genotoxic activity under the experimental conditions employed were only genotoxic in the presence of S9 mix (10%). The results obtained were correlated with models of the metabolic activation of nitrosamines in an attempt to rationalize the genotoxicity of these compounds. The results show that the presence of substituents in the nitrosopiperidine molecule may be one of the modulating factors affecting the genotoxicity of these cyclic nitrosamines, and may help provide some chemical clues for the identification of risk compounds from among a large group of structurally related molecules.
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Affiliation(s)
- Samuel González-Mancebo
- Departamento de Química Física, Facultad de Química, Universidad de Salamanca, E-37008 Salamanca, Spain
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del Pilar Garcı́a Santos M, Calle E, Casado J. A method for the kinetic study of amino acid nitrosation reactions. Polyhedron 2003. [DOI: 10.1016/s0277-5387(03)00091-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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García-Santos MDP, González-Mancebo S, Hernández-Benito J, Calle E, Casado J. Reactivity of amino acids in nitrosation reactions and its relation to the alkylating potential of their products. J Am Chem Soc 2002; 124:2177-82. [PMID: 11878971 DOI: 10.1021/ja0119503] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nitrosation reactions of amino acids with an -NH(2) group [namely, six alpha-amino acids (glycine, alanine, alpha-aminobutyric acid, alpha-aminoisobutyric acid, valine, and norvaline); two beta-amino acids (beta-alanine and beta-aminobutyric acid), and one gamma-amino acid (gamma-aminobutyric acid)] were studied. Nitrosation was carried out in aqueous acid media, mimicking the conditions of the stomach lumen. The rate equation was r = k(3)(exp)[amino acid][nitrite](2), with a maximum k(3)(exp) value in the 2.3-2.7 pH range. The existence of an isokinetic relationship supports the argument that all the reactions share a common mechanism. A nitrosation mechanism is proposed, and the following conclusions are drawn: (i) Nitrosation reactions of amino acids with a primary amino group in acid media occur with dinitrogen trioxide as the main nitrosating agent. The finding that the nitrosation rate is proportional to the square of the nitrite concentration suggests that the yield of nitrosation products in the stomach would increase sharply with higher nitrate/nitrite intakes. (ii) Stomach hypochlorhydria could be a potential enhancer of in vivo amino acid nitrosation. (iii) The reactivity (k(3)()(exp)) [alpha-amino acids > beta-amino acids > gamma-amino acids] is the same as that found in a previous work for the alkylating potential of lactones formed from nitrosation products of the same amino acids. This implies that the nitrosation reactions of the most common natural amino acids are the most efficient precursors of the most powerful alkylating agents. (iv) The order of magnitude (10(7)-10(8) M(-1) s(-1)) of the bimolecular rate constants of nitrosation shows that such reactions occur through an encounter process.
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Margison GP, Santibáñez-Koref MF. O6-alkylguanine-DNA alkyltransferase: role in carcinogenesis and chemotherapy. Bioessays 2002; 24:255-66. [PMID: 11891762 DOI: 10.1002/bies.10063] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The DNA in human cells is continuously undergoing damage as consequences of both endogenous processes and exposure to exogenous agents. The resulting structural changes can be repaired by a number of systems that function to preserve genome integrity. Most pathways are multicomponent, involving incision in the damaged DNA strand and resynthesis using the undamaged strand as a template. In contrast, O(6)-alkylguanine-DNA alkyltransferase is able to act as a single protein that reverses specific types of alkylation damage simply by removing the offending alkyl group, which becomes covalently attached to the protein and inactivates it. The types of damage that ATase repairs are potentially toxic, mutagenic, recombinogenic and clastogenic. They are generated by certain classes of carcinogenic and chemotherapeutic alkylating agents. There is consequently a great deal of interest in this repair system in relation to both carcinogenesis and cancer chemotherapy.
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Affiliation(s)
- Geoffrey P Margison
- CRC Carcinogenesis Group, Paterson Institute for Cancer Research, Manchester, UK
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