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Li M, Ho CT, Wang J, Hu Y, Zhai X, Zhang L, Wan X, Yang X. Formation of Volatile Heterocyclic Compounds and Open-Chain Amides of Theanine in Model Systems with Glucose, Tea Leaves, and Tea Extract under Tea-Roasting Conditions. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:6737-6746. [PMID: 35621700 DOI: 10.1021/acs.jafc.2c02039] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Theanine is a non-proteinogenic amino acid found in the tea plant Camellia sinensis. At an elevated temperature (>90 °C), it released two major volatile compounds 1-ethyl-1,5-dihydro-2H-pyrrol-2-one and N-ethylsuccinimide. Other products were identified, including 10 pyrroles and 12 amides/imides. The formation of the two major compounds was proposed to be initiated by the deamination of theanine and through the intermediate α-keto acid. In the presence of glucose, the two major products and many other volatiles from theanine thermal degradation were accelerated and further Maillard reactions occurred. A total of 56 compounds were identified in the model system of theanine and glucose, including 12 amides/imides, 16 pyrazines, 16 pyrroles and other N-heterocycles, and 12 furans and other O-heterocycles. Although most of the reaction products were detected in tea leaves and in their aqueous extract with or without the addition of theanine under the same experiment conditions, imides and amides were considerably suppressed, left only minute amounts, or were even no longer detectable. Pyrazines and pyrroles were also shown at reduced concentrations as a result of the interaction with tea components but to a lesser extent. A total of 16 and 12 pyrazines were identified in the theanine/glucose reaction system and tea leaves/aqueous extract after roasting, respectively. The results indicated that pyrazines and other main volatiles in roasted tea leaves were formed from the Maillard reactions of the aqueous fraction of tea leaves. Theanine participated in the formation of pyrazines in tea leaves under roasting conditions.
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Affiliation(s)
- Mengru Li
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China
| | - Chi-Tang Ho
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China
- Department of Food Science, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, United States
| | - Jing Wang
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China
| | - Yuemeng Hu
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China
| | - Xiaoting Zhai
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China
| | - Liang Zhang
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China
| | - Xiaochun Wan
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China
| | - Xiaogen Yang
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China
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Nakayoshi T, Kato K, Kurimoto E, Takano Y, Oda A. Predicting Reaction Mechanisms for the Threonine-Residue Stereoinversion Catalyzed by a Dihydrogen Phosphate Ion. ACS OMEGA 2022; 7:18306-18314. [PMID: 35694452 PMCID: PMC9178615 DOI: 10.1021/acsomega.2c00372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 05/18/2022] [Indexed: 06/15/2023]
Abstract
The stereoinversion of amino acid residues in proteins is considered to trigger various age-related diseases. Serine (Ser) residues are relatively prone to stereoinversion. It is assumed that threonine (Thr) residues also undergo stereoinversion, which results in the formation of the d-allo-Thr residue, by the same mechanisms as those for Ser-residue stereoinversion; however, d-allo-Thr residues have not been detected in vivo. To date, although Ser-residue stereoinversion has been suggested to progress via enolization, plausible reaction mechanisms for Thr-residue stereoinversion have not been proposed. In this study, we investigated the pathway of Thr-residue enolization and successfully identified the three types of plausible reaction pathways of Thr-residue stereoinversion catalyzed by a dihydrogen phosphate ion. The geometries of reactant complexes, transition states, and enolized product complexes were optimized using B3LYP density functional methods, and single-point calculations were performed for all optimized geometries using Møller-Plesset perturbation theory to obtain reliable energies. As a result, the calculated activation energies of Thr-residue stereoinversion were 105-106 kJ mol-1, which were comparable with those of Ser-residue stereoinversion reported previously. The infrequency of Thr-residue stereoinversion may be due to other factors, such as the hydrophobicity and/or the steric hindrance of the γ-methyl group, rather than the high activation energies.
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Affiliation(s)
- Tomoki Nakayoshi
- Graduate
School of Information Sciences, Hiroshima
City University, 3-4-1 Ozukahigashi, Asaminami-ku, Hiroshima, Hiroshima 731-3194, Japan
- Faculty
of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya, Aichi 468-8503, Japan
- Institute
of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Koichi Kato
- Faculty
of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya, Aichi 468-8503, Japan
- Faculty
of Pharmaceutical Sciences, Shonan University
of Medical Sciences, 16-48 Kamishinano, Totsuka-ku, Yokohama, Kanagawa 244-0806, Japan
- College
of Pharmacy, Kinjo Gakuin University, 2-1723 Omori, Moriyama-ku, Nagoya, Aichi 463-8521, Japan
| | - Eiji Kurimoto
- Faculty
of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya, Aichi 468-8503, Japan
| | - Yu Takano
- Graduate
School of Information Sciences, Hiroshima
City University, 3-4-1 Ozukahigashi, Asaminami-ku, Hiroshima, Hiroshima 731-3194, Japan
- Institute
for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Akifumi Oda
- Faculty
of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya, Aichi 468-8503, Japan
- Institute
of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
- Institute
for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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Nakayoshi T, Wanita K, Kato K, Kurimoto E, Oda A. Computational analysis of nonenzymatic deamidation of asparagine residues catalysed by acetic acid. Mol Phys 2021. [DOI: 10.1080/00268976.2020.1827176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Tomoki Nakayoshi
- Graduate School of Pharmacy, Meijo University, Nagoya, Japan
- Institute of Medical, Pharmaceutical and Health Science, Kanazawa University, Kanazawa, Japan
| | - Kota Wanita
- Graduate School of Pharmacy, Meijo University, Nagoya, Japan
| | - Koichi Kato
- Graduate School of Pharmacy, Meijo University, Nagoya, Japan
- Department of Pharmacy, Kinjo Gakuin University, Nagoya, Japan
| | - Eiji Kurimoto
- Graduate School of Pharmacy, Meijo University, Nagoya, Japan
| | - Akifumi Oda
- Graduate School of Pharmacy, Meijo University, Nagoya, Japan
- Institute of Medical, Pharmaceutical and Health Science, Kanazawa University, Kanazawa, Japan
- Institute for Protein Research, Suita, Japan
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Nakayoshi T, Kato K, Kurimoto E, Oda A. Computational Studies on the Mechanisms of Nonenzymatic Intramolecular Cyclization of the Glutamine Residues Located at N-Termini Catalyzed by Inorganic Phosphate Species. ACS OMEGA 2020; 5:9162-9170. [PMID: 32363268 PMCID: PMC7191561 DOI: 10.1021/acsomega.9b04384] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 04/02/2020] [Indexed: 05/13/2023]
Abstract
Glutamine (Gln) residues located at N-termini undergo spontaneous intramolecular cyclization, causing the formation of pyroglutamic acid (pGlu) residues. pGlu residues have been detected at the N-termini in various peptides and proteins. The formation of pGlu residues during the fermentation and purification processes of antibody drugs is one of the concerns in the design and formulation of these drugs and has been reported to proceed rapidly in a phosphate buffer. In this study, we have examined the phosphate-catalyzed mechanisms of the pGlu residue formation from N-terminal Gln residues via quantum chemical calculations using B3LYP density functional methods. Single-point energies were calculated using the second-order Møller-Plesset perturbation theory. We performed the calculations for the model compound in which an uncharged N-terminal Gln residue is capped with a methyl amino group on the C-terminal. The activation energy of the formation of pGlu residues was calculated as 83.8 kJ mol-1, which was lower than that of the typical nonenzymatic reaction of amino acid residues. In addition, the computational results indicate that the flexibility of the main and side chains in N-terminal Gln residues was necessary for the formation of pGlu residues to proceed. In the obtained pathway, inorganic phosphate species act as the catalyst by mediating the proton transfer.
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Affiliation(s)
- Tomoki Nakayoshi
- Graduate
School of Pharmacy, Meijo University, 150 Yagotoyama,
Tempaku-ku, Nagoya, Aichi 468-8503, Japan
- Institute
of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Koichi Kato
- Graduate
School of Pharmacy, Meijo University, 150 Yagotoyama,
Tempaku-ku, Nagoya, Aichi 468-8503, Japan
- Department
of Pharmacy, Kinjo Gakuin University, 2-1723 Omori, Moriyama-ku, Nagoya, Aichi 463-8521, Japan
| | - Eiji Kurimoto
- Graduate
School of Pharmacy, Meijo University, 150 Yagotoyama,
Tempaku-ku, Nagoya, Aichi 468-8503, Japan
| | - Akifumi Oda
- Graduate
School of Pharmacy, Meijo University, 150 Yagotoyama,
Tempaku-ku, Nagoya, Aichi 468-8503, Japan
- Institute
of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
- Institute
for Protein Research, Osaka University, 3-2 Yamadaoka,
Suita, Osaka 565-0871, Japan
- . Phone: +81-52-832-1151
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Nakayoshi T, Kato K, Kurimoto E, Oda A. Computational studies on nonenzymatic pyroglutamylation mechanism of N-terminal glutamic acid residues in aqueous conditions*. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1702727] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Tomoki Nakayoshi
- Graduate School of Pharmacy, Meijo University, Nagoya, Japan
- Institute of Medical, Pharmaceutical and Health Science, Kanazawa University, Kanazawa, Japan
| | - Koichi Kato
- Graduate School of Pharmacy, Meijo University, Nagoya, Japan
- Department of Pharmacy, Kinjo Gakuin University, Nagoya, Japan
| | - Eiji Kurimoto
- Graduate School of Pharmacy, Meijo University, Nagoya, Japan
| | - Akifumi Oda
- Graduate School of Pharmacy, Meijo University, Nagoya, Japan
- Institute of Medical, Pharmaceutical and Health Science, Kanazawa University, Kanazawa, Japan
- Institute for Protein Research, Osaka, Japan
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