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Truong DH, Lan Nguyen TH, Dao DQ. Revisiting the HO ●-initiated oxidation of L-proline amino acid in the aqueous phase: influence of transition metal ions. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230114. [PMID: 37293362 PMCID: PMC10245202 DOI: 10.1098/rsos.230114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 05/02/2023] [Indexed: 06/10/2023]
Abstract
The oxidation of L-proline (Pro) by HO● radical in water and the influence of transition metal ions on this process has been revisited by using the density functional theory (DFT) method at the M05-2X/6-311 + + G(3df,3pd)//M05-2X/6-311 + + G(d,p) level of theory at the temperature of 298.15 K. The main reactive sites of the HO●-initiated oxidation of Pro via hydrogen atom transfer (HAT) reactions are at the β- and γ-carbon, with the branching ratios being 44.6% and 39.5%, respectively. The overall rate constant at 298.15 K is 6.04 × 108 M-1 s-1. In addition, Pro tends to form stable complexes with both Fe and Cu ions via the -COO functional group of dipole-salt form. The most stable Cu(II)-Pro complexes have high oxidant risks in enhancing the HO● formation in the presence of reducing agents. Besides this, the high oxidation state metal complexes, i.e. Fe(III)-Pro and Cu(II)-Pro, may be oxidized by HO● radical via HAT reactions but with a lower rate constant than that of free-Pro. By contrast, the low oxidation state metal complexes (i.e. Fe(II)-Pro and Cu(I)-Pro) have higher oxidation risks than the free ligands, and thus, the complexation enhances the oxidation of Pro amino acid.
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Affiliation(s)
- Dinh Hieu Truong
- Institute of Research and Development, Duy Tan University, Da Nang 550000, Vietnam
- Faculty of Natural Sciences, Duy Tan University, Da Nang 550000, Vietnam
| | | | - Duy Quang Dao
- Institute of Research and Development, Duy Tan University, Da Nang 550000, Vietnam
- Faculty of Natural Sciences, Duy Tan University, Da Nang 550000, Vietnam
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Keshavarz F, Mazarei E. From Kinetics of OH Reaction with Glutamic Acid to Oxidative Damage to Proteins. J Phys Chem A 2019; 123:429-442. [DOI: 10.1021/acs.jpca.8b08664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Fatemeh Keshavarz
- Department of Chemistry, College of Science, Shiraz University, Shiraz, Iran
| | - Elham Mazarei
- Department of Chemistry, College of Science, Shiraz University, Shiraz, Iran
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Uranga J, Mujika JI, Grande-Aztatzi R, Matxain JM. Oxidation of Acid, Base, and Amide Side-Chain Amino Acid Derivatives via Hydroxyl Radical. J Phys Chem B 2018; 122:4956-4971. [PMID: 29676577 DOI: 10.1021/acs.jpcb.7b12450] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Hydroxyl radical (•OH) is known to be highly reactive. Herein, we analyze the oxidation of acid (Asp and Glu), base (Arg and Lys), and amide (Asn and Gln) containing amino acid derivatives by the consecutive attack of two •OH. In this work, we study the reaction pathway by means of density functional theory. The oxidation mechanism is divided into two steps: (1) the first •OH can abstract a H atom or an electron, leading to a radical amino acid derivative, which is the intermediate of the reaction and (2) the second •OH can abstract another H atom or add itself to the formed radical, rendering the final oxidized products. The studied second attack of •OH is applicable to situations where high concentration of •OH is found, e.g., in vitro. Carbonyls are the best known oxidation products for these reactions. This work includes solvent dielectric and confirmation's effects of the reaction, showing that both are negligible. Overall, the most favored intermediates of the oxidation process at the side chain correspond to the secondary radicals stabilized by hyperconjugation. Intermediates show to be more stable in those cases where the spin density of the unpaired electron is lowered. Alcohols formed at the side chains are the most favored products, followed by the double-bond-containing ones. Interestingly, Arg and Lys side-chain scission leads to the most favored carbonyl-containing oxidation products, in line with experimental results.
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Affiliation(s)
- Jon Uranga
- Kimika Fakultatea-Chemistry Department , Euskal Herriko Unibertsitatea (UPV/EHU) , P.K. 1072 , 20080 Donostia , Euskadi , Spain.,Donostia International Physics Center (DIPC) , Manuel Lardizabal 4 , 20018 Donostia , Euskadi , Spain
| | - Jon I Mujika
- Donostia International Physics Center (DIPC) , Manuel Lardizabal 4 , 20018 Donostia , Euskadi , Spain
| | - Rafael Grande-Aztatzi
- Donostia International Physics Center (DIPC) , Manuel Lardizabal 4 , 20018 Donostia , Euskadi , Spain
| | - Jon M Matxain
- Kimika Fakultatea-Chemistry Department , Euskal Herriko Unibertsitatea (UPV/EHU) , P.K. 1072 , 20080 Donostia , Euskadi , Spain.,Donostia International Physics Center (DIPC) , Manuel Lardizabal 4 , 20018 Donostia , Euskadi , Spain
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4
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Kecel-Gunduz S, Bicak B, Celik S, Akyuz S, Ozel AE. Structural and spectroscopic investigation on antioxidant dipeptide, l -Methionyl- l -Serine: A combined experimental and DFT study. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.02.075] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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5
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Protein Stability and Unfolding Following Glycine Radical Formation. Molecules 2017; 22:molecules22040655. [PMID: 28422069 PMCID: PMC6154654 DOI: 10.3390/molecules22040655] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 04/12/2017] [Accepted: 04/13/2017] [Indexed: 02/02/2023] Open
Abstract
Glycine (Gly) residues are particularly susceptible to hydrogen abstraction; which results in the formation of the capto-dative stabilized Cα-centered Gly radical (GLR) on the protein backbone. We examined the effect of GLR formation on the structure of the Trp cage; tryptophan zipper; and the villin headpiece; three fast-folding and stable miniproteins; using all-atom (OPLS-AA) molecular dynamics simulations. Radicalization changes the conformation of the GLR residue and affects both neighboring residues but did not affect the stability of the Trp zipper. The stability of helices away from the radical center in villin were also affected by radicalization; and GLR in place of Gly15 caused the Trp cage to unfold within 1 µs. These results provide new evidence on the destabilizing effects of protein oxidation by reactive oxygen species.
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6
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Uranga J, Lakuntza O, Ramos-Cordoba E, Matxain JM, Mujika JI. A computational study of radical initiated protein backbone homolytic dissociation on all natural amino acids. Phys Chem Chem Phys 2016; 18:30972-30981. [DOI: 10.1039/c6cp06529e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydroxyl radical (˙OH) is known to be one of the most reactive species. The attack of this radical onto the backbone of all natural amino acids is investigated.
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Affiliation(s)
- Jon Uranga
- Kimika Fakultatea
- Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC)
- 20080 Donostia
- Spain
| | - Oier Lakuntza
- Institut Catala d'Investigacio Quimica (ICIQ)
- 43007 Tarragona
- Spain
| | - Eloy Ramos-Cordoba
- Kimika Fakultatea
- Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC)
- 20080 Donostia
- Spain
- Department of Chemistry
| | - Jon M. Matxain
- Kimika Fakultatea
- Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC)
- 20080 Donostia
- Spain
| | - Jon I. Mujika
- Kimika Fakultatea
- Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC)
- 20080 Donostia
- Spain
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Uranga J, Mujika JI, Matxain JM. ·OH Oxidation Toward S- and OH-Containing Amino Acids. J Phys Chem B 2015; 119:15430-42. [DOI: 10.1021/acs.jpcb.5b09825] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Jon Uranga
- Kimika Fakultatea,
Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International
Physics Center (DIPC), P.K. 1072, 20080 Donostia, Euskadi, Spain
| | - Jon I. Mujika
- Kimika Fakultatea,
Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International
Physics Center (DIPC), P.K. 1072, 20080 Donostia, Euskadi, Spain
| | - Jon M. Matxain
- Kimika Fakultatea,
Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International
Physics Center (DIPC), P.K. 1072, 20080 Donostia, Euskadi, Spain
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Medina ME, Galano A, Alvarez-Idaboy JR. Site reactivity in the free radicals induced damage to leucine residues: a theoretical study. Phys Chem Chem Phys 2015; 17:4970-6. [DOI: 10.1039/c4cp05688d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The reactions of leucine with free radicals are kinetically controlled and are faster in hydrophilic than in hydrophobic media.
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Affiliation(s)
- M. E. Medina
- Departamento de Física y Química Teórica
- Facultad de Química
- Universidad Nacional Autónoma de México
- México D. F. 04510
- Mexico
| | - A. Galano
- Departamento de Química
- División de Ciencias Básicas e Ingeniería
- Universidad Autónoma Metropolitana-Iztapalapa
- México D. F. 09340
- Mexico
| | - J. R. Alvarez-Idaboy
- Departamento de Física y Química Teórica
- Facultad de Química
- Universidad Nacional Autónoma de México
- México D. F. 04510
- Mexico
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Zhao X, Geng Z, Yang H, Wang D, Ding W, Liu J. Theoretical investigations on the reaction kinetics of CH3OCl/CD3OCl with chloride ion. COMPUT THEOR CHEM 2014. [DOI: 10.1016/j.comptc.2014.01.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Lin RJ, Jang S, Kim H, Wu CC, Li FY. Site specificity on OH α-H abstraction reaction for a zwitterionic β-hairpin peptide in aqueous solution: a theoretical investigation. J Phys Chem B 2013; 117:771-83. [PMID: 23252826 DOI: 10.1021/jp308879r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Protein backbone oxidation was investigated by studying the α-H abstraction reaction in a ß-hairpin peptide, called Chignolin (PDB ID 1UAO), with density functional theory calculation at B3LYP/6-31G(d,p) without any constraint. In order to stabilize the zwitterionic form of Chignolin with the salt bridges, the effects of aqueous solution were implemented by using microsolvation combined with a conductor-like polarizable continuum model (CPCM). Comparison between three glycine residues located at three different sites in Chignolin was used to examine the possible site specificity of this backbone oxidation. To construct the reaction profile of these α-H abstraction reactions, the pre- and postreactive complexes along with their associated transition states were located and verified with the intrinsic reaction coordinate (IRC) method. The bond dissociation energy and reaction rates of these OH α-H abstraction reactions were calculated with transition state theory. The differences in this abstraction reaction between the neutral and zwitterionic forms of Chignolin were also compared. A molecular dynamics simulation was implemented to study the explicit solvation effect on the abstracted Chignolin structure. The range of the simulation time scale covers from femtoseconds to microseconds, i.e., from onset of the abstraction to the abstracted products reaching thermal equilibrium. Our results show that there are three kinds of site-specificity in this abstraction reaction. The reactivity and stability of the abstraction products and their abstraction modes are all dependent on the location where OH attacks. Furthermore, the free energy landscapes of these abstraction products are distinctively different. This may imply that the pathological disorders or diseases caused by this type of radicals are also dependent on the abstraction location.
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Affiliation(s)
- Ren-Jie Lin
- Department of Chemistry, National Chung Hsing University, Taichung, Taiwan 402, Republic of China
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Chan B, O’Reilly RJ, Easton CJ, Radom L. Reactivities of Amino Acid Derivatives Toward Hydrogen Abstraction by Cl• and OH•. J Org Chem 2012; 77:9807-12. [DOI: 10.1021/jo3021538] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Bun Chan
- School of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Robert J. O’Reilly
- School of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | | | - Leo Radom
- School of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
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Chen HY, Jang S, Jinn TR, Chang JY, Lu HF, Li FY. Oxygen radical-mediated oxidation reactions of an alanine peptide motif - density functional theory and transition state theory study. Chem Cent J 2012; 6:33. [PMID: 22524792 PMCID: PMC3353240 DOI: 10.1186/1752-153x-6-33] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 04/24/2012] [Indexed: 02/11/2023] Open
Abstract
Background Oxygen-base (O-base) oxidation in protein backbone is important in the protein backbone fragmentation due to the attack from reactive oxygen species (ROS). In this study, an alanine peptide was used model system to investigate this O-base oxidation by employing density functional theory (DFT) calculations combining with continuum solvent model. Detailed reaction steps were analyzed along with their reaction rate constants. Results Most of the O-base oxidation reactions for this alanine peptide are exothermic except for the bond-breakage of the Cα-N bond to form hydroperoxy alanine radical. Among the reactions investigated in this study, the activated energy of OH α-H abstraction is the lowest one, while the generation of alkylperoxy peptide radical must overcome the highest energy barrier. The aqueous situation facilitates the oxidation reactions to generate hydroxyl alanine peptide derivatives except for the fragmentations of alkoxyl alanine peptide radical. The Cα-Cβ bond of the alkoxyl alanine peptide radical is more labile than the peptide bond. Conclusion the rate-determining step of oxidation in protein backbone is the generation of hydroperoxy peptide radical via the reaction of alkylperoxy peptide radical with HO2. The stabilities of alkylperoxy peptide radical and complex of alkylperoxy peptide radical with HO2 are crucial in this O-base oxidation reaction.
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Affiliation(s)
- Hsing-Yu Chen
- Department of Chemistry, National Chung Hsing University, Taichung, Taiwan 402, R,O,C.
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Salamone M, DiLabio GA, Bietti M. Hydrogen atom abstraction selectivity in the reactions of alkylamines with the benzyloxyl and cumyloxyl radicals. The importance of structure and of substrate radical hydrogen bonding. J Am Chem Soc 2011; 133:16625-34. [PMID: 21895002 DOI: 10.1021/ja206890y] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A time-resolved kinetic study on the hydrogen abstraction reactions from a series of primary and secondary amines by the cumyloxyl (CumO(•)) and benzyloxyl (BnO(•)) radicals was carried out. The results were compared with those obtained previously for the corresponding reactions with tertiary amines. Very different hydrogen abstraction rate constants (k(H)) and intermolecular selectivities were observed for the reactions of the two radicals. With CumO(•), k(H) was observed to decrease on going from the tertiary to the secondary and primary amines. The lowest k(H) values were measured for the reactions with 2,2,6,6-tetramethylpiperidine (TMP) and tert-octylamine (TOA), substrates that can only undergo N-H abstraction. The opposite behavior was observed for the reactions of BnO(•), where the k(H) values increased in the order tertiary < secondary < primary. The k(H) values for the reactions of BnO(•) were in all cases significantly higher than those measured for the corresponding reactions of CumO(•), and no significant difference in reactivity was observed between structurally related substrates that could undergo exclusive α-C-H and N-H abstraction. This different behavior is evidenced by the k(H)(BnO(•))/k(H)(CumO(•)) ratios that range from 55-85 and 267-673 for secondary and primary alkylamines up to 1182 and 3388 for TMP and TOA. The reactions of CumO(•) were described in all cases as direct hydrogen atom abstractions. With BnO(•) the results were interpreted in terms of the rate-determining formation of a hydrogen-bonded prereaction complex between the radical α-C-H and the amine lone pair wherein hydrogen abstraction occurs. Steric effects and amine HBA ability play a major role, whereas the strength of the substrate α-C-H and N-H bonds involved appears to be relatively unimportant. The implications of these different mechanistic pictures are discussed.
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Affiliation(s)
- Michela Salamone
- Dipartimento di Scienze e Tecnologie Chimiche, Università Tor Vergata, Via della Ricerca Scientifica, 1 I-00133 Rome, Italy
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Lin RJ, Jang S, Wu CC, Liu YL, Li FY. Site specificity of OH α-H abstraction reaction for a β-hairpin peptide: An ab initio study. J Comput Chem 2011; 32:3409-22. [DOI: 10.1002/jcc.21920] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 07/01/2011] [Accepted: 07/25/2011] [Indexed: 12/13/2022]
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Liessmann M, Hansmann B, Blachly PG, Francisco JS, Abel B. Primary Steps in the Reaction of OH Radicals with Amino Acids at Low Temperatures in Laval Nozzle Expansions: Perspectives from Experiment and Theory. J Phys Chem A 2009; 113:7570-5. [DOI: 10.1021/jp9015596] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Matthias Liessmann
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany, Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, and W.-Ostwald-Institut für Physikalische und Theoretische Chemie der Universität Leipzig, Linné-Strasse 2, D-04103 Leipzig, Germany
| | - Björn Hansmann
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany, Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, and W.-Ostwald-Institut für Physikalische und Theoretische Chemie der Universität Leipzig, Linné-Strasse 2, D-04103 Leipzig, Germany
| | - Patrick G. Blachly
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany, Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, and W.-Ostwald-Institut für Physikalische und Theoretische Chemie der Universität Leipzig, Linné-Strasse 2, D-04103 Leipzig, Germany
| | - Joseph S. Francisco
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany, Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, and W.-Ostwald-Institut für Physikalische und Theoretische Chemie der Universität Leipzig, Linné-Strasse 2, D-04103 Leipzig, Germany
| | - Bernd Abel
- Institut für Physikalische Chemie der Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany, Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, and W.-Ostwald-Institut für Physikalische und Theoretische Chemie der Universität Leipzig, Linné-Strasse 2, D-04103 Leipzig, Germany
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Cheng WC, Jang S, Wu CC, Lin RJ, Lu HF, Li FY. Site specificity of theαCH bond dissociation energy for a naturally occurring β-hairpin peptide-Anab initiostudy. J Comput Chem 2009; 30:407-14. [DOI: 10.1002/jcc.21066] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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17
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Lu HF, Li FY, Lin SH. Site specificity of α-H abstraction reaction among secondary structure motif—Anab initio study. J Comput Chem 2007; 28:783-94. [PMID: 17226837 DOI: 10.1002/jcc.20605] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The initial step of protein oxidation is studied through alpha-H abstraction by an OH radical with various secondary structure motifs of proteins. It is found that there exist preferential alpha-Hs in this kind of abstractions. The typical abstraction mechanism involves three steps: forming a pre-reactive complex before abstraction, the abstraction reaction, and the H(2)O detachment from a post-reactive complex to form the product, C(alpha)-center radical. Using the stability of the pre-reactive complex and the reaction barrier, we provide some explanation for this site preference. The feasibility of alpha-H abstraction by OH radical depends not only on the types of secondary structure, but also on the reaction condition, such as in aqueous or in gas phase. Moreover, the reactivity of the abstraction also depends on the location of alpha-H in the secondary structure motifs. The preferential alpha-Hs to be abstracted in beta-sheet are those immediate to the amide or carbonyl group, and without involving hydrogen bonding, whereas in reverse turns, the preferential alpha-Hs are near the C-terminal of type I and near the N-terminal of type II. In general, the alpha-Hs in alpha-helix are more difficult to be abstracted than those in beta-sheet and polypeptide in linear form. It is consistent with the trend of their bond dissociation energies. Our theoretical rate constant of N-acetyldiglycin-methylamide (Ac(Gly)(2)NHCH(3)) in aqueous solution (6.75 x 10(8) M(-1) s(-1)) is close to the experimental observation of N-acetyldiglycinamide (Ac(Gly)(2)NH(2)) (8.6 x 10(8) M(-1) s(-1)).
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Affiliation(s)
- Hsiu-Feng Lu
- The Institute of Atomic and Molecular Sciences, Academia Sinica, P. O. Box 23-166, Taipei, Taiwan 106, Republic of China.
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Cruz-Torres A, Galano A, Alvarez-Idaboy JR. Kinetics and mechanism of the β-alanine + OH gas phase reaction: A quantum mechanical approach. Phys Chem Chem Phys 2006; 8:285-92. [PMID: 16482271 DOI: 10.1039/b507101a] [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] [Indexed: 01/10/2023]
Abstract
The OH hydrogen abstraction reaction from beta-alanine has been studied using the BHandHLYP hybrid HF-density functional and 6-311G(d,p) basis sets. The energies have been improved by single point calculations at the CCSD(T)/6-311G(d,p) level of theory. The structures of the different stationary points are discussed. Reaction profiles are modeled including the formation of pre-reactive and product complexes. Negative net activation energy is obtained for the overall reaction. A complex mechanism is proposed, and the rate coefficients are calculated using transition state theory over the temperature range of 250-400 K. The rate coefficients are proposed for the first time and it was found that in the gas phase the hydrogen abstraction occurs mainly from the CH(2) group next to the amino end. The following expressions, in cm(3) mol(-1) s(-1), are obtained for the overall rate constants, at 250-400 and 290-310 K, respectively: k(250-400)= 2.36 x 10(-12) exp(340/T), and k(290-310)= 1.296 x 10(-12) exp(743/T). The three parameter expression that best describes the studied reaction is k(250-400)= 1.01 x 10(-21)T(3.09) exp(1374/T). The beta-alanine + OH reaction was found to be 1.5 times faster than the alpha-alanine + OH reaction.
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Affiliation(s)
- Armando Cruz-Torres
- Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas 152, 007730 México D. F., México
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