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Zhang FS, Yang Y, Bian X, Ma CM, Ren LK, Zhang C, Pang XH, Zhang N. The structural and functional properties of hemp protein isolate-epigallocatechin-3-gallate biopolymer covalent complex during heating. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2024; 104:2484-2492. [PMID: 37972116 DOI: 10.1002/jsfa.13135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 10/31/2023] [Accepted: 11/17/2023] [Indexed: 11/19/2023]
Abstract
BACKGROUND It is well known that hemp proteins have the disadvantages of poor solubility and poor emulsification. To improve these shortcomings, an alkali covalent cross-linking method was used to prepare hemp protein isolate-epigallocatechin-3-gallate biopolymer (HPI-EGCG) and the effects of different heat treatment conditions on the structure and emulsifying properties of the HPI-EGCG covalent complex were studied. RESULTS The secondary and tertiary structures, solubility, and emulsification ability of the HPI-EGCG complexes were evaluated using particle size, zeta potential, circular dichroism (CD), and fluorescence spectroscopy indices. The results showed that the absolute value of zeta potential of HPI-EGCG covalent complex was the largest, 18.6 mV, and the maximum binding amount of HPI to EGCG was 29.18 μmol g-1 . Under heat treatment at 25-35 °C, the α-helix content was reduced from 1.87% to 0%, and the β-helix content was reduced from 82.79% to 0% after the covalent binding of HPI and EGCG. The solubility and emulsification properties of the HPI-EGCG covalent complexes were improved significantly, and the emulsification activity index (EAI) and emulsion stability index (ESI) were increased by 2.77-fold and 1.21-fold, respectively. CONCLUSION A new HPI-EGCG covalent complex was developed in this study to provide a theoretical basis for the application of HPI-EGCG in food industry. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Fu-Shun Zhang
- College of Food Engineering, Harbin University of Commerce, Harbin, China
| | - Yang Yang
- College of Food Engineering, Harbin University of Commerce, Harbin, China
| | - Xin Bian
- College of Food Engineering, Harbin University of Commerce, Harbin, China
| | - Chun-Min Ma
- College of Food Engineering, Harbin University of Commerce, Harbin, China
| | - Li-Kun Ren
- College of Food Engineering, Harbin University of Commerce, Harbin, China
| | - Can Zhang
- College of Food Engineering, Harbin University of Commerce, Harbin, China
| | - Xin-Hui Pang
- College of Food Engineering, Harbin University of Commerce, Harbin, China
| | - Na Zhang
- College of Food Engineering, Harbin University of Commerce, Harbin, China
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Ashirbaev SS, Brás NF, Frei P, Liu K, Moser S, Zipse H. Redox-Mediated Amination of Pyrogallol-Based Polyphenols. Chemistry 2024; 30:e202303783. [PMID: 38029366 DOI: 10.1002/chem.202303783] [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: 11/15/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 12/01/2023]
Abstract
Flavonoids are known to covalently modify amyloidogenic peptides by amination reactions. The underlying coupling process between polyphenols and N-nucleophiles is assessed by several in vitro and in silico approaches. The coupling reaction involves a sequence of oxidative dearomatization, amination, and reductive amination (ODARA) reaction steps. The C6-regioselectivity of the product is confirmed by crystallographic analysis. Under aqueous conditions, the reaction of baicalein with lysine derivatives yields C-N coupling as well as hydrolysis products of transient imine intermediates. The observed C-N coupling reactions work best for flavonoids combining a pyrogallol substructure with an electron-withdrawing group attached to the C4a-position. Thermodynamic properties such as bond dissociation energies also highlight the key role of pyrogallol units for the antioxidant ability. Combining the computed electronic properties and in vitro antioxidant assays suggests that the studied pyrogallol-containing flavonoids act by various radical-scavenging mechanisms working in synergy. Multivariate analysis indicates that a small number of descriptors for transient intermediates of the ODARA process generates a model with excellent performance (r=0.93) for the prediction of cross-coupling yields. The same model has been employed to predict novel antioxidant flavonoid-based molecules as potential covalent inhibitors, opening a new avenue to the design of therapeutically relevant anti-amyloid compounds.
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Affiliation(s)
- Salavat S Ashirbaev
- Department of Chemistry, Ludwig Maximilian University of Munich, Butenandtstraße 5-13, 81377, Munich, Germany
| | - Natércia F Brás
- Department of Chemistry, Ludwig Maximilian University of Munich, Butenandtstraße 5-13, 81377, Munich, Germany
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal
| | - Patricia Frei
- Department of Pharmacy, Ludwig Maximilian University of Munich, Butenandtstraße 5-13, 81377, Munich, Germany
| | - Kuangjie Liu
- Department of Chemistry, Ludwig Maximilian University of Munich, Butenandtstraße 5-13, 81377, Munich, Germany
| | - Simone Moser
- Institute of Pharmacy, University of Innsbruck, Innrain 80-13, 6020, Innsbruck, Austria
| | - Hendrik Zipse
- Department of Chemistry, Ludwig Maximilian University of Munich, Butenandtstraße 5-13, 81377, Munich, Germany
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Li D, Zhu L, Wu Q, Chen Y, Wu G, Zhang H. Tartary buckwheat protein-phenol conjugate prepared by alkaline-based environment: Identification of covalent binding sites of phenols and alterations in protein structural and functional characteristics. Int J Biol Macromol 2024; 257:127504. [PMID: 37858650 DOI: 10.1016/j.ijbiomac.2023.127504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/17/2023] [Accepted: 10/11/2023] [Indexed: 10/21/2023]
Abstract
Tartary buckwheat protein-rutin/quercetin covalent complex was synthesized in alkaline oxygen-containing environment, and its binding sites, conformational changes and functional properties were evaluated by multispectral technique and proteomics. The determination of total sulfhydryl and free amino groups showed that rutin/quercetin can form a covalent complex with BPI and could significantly reduce the group content. Ultraviolet-visible spectrum analysis showed that protein could form new characteristic peaks after binding with rutin/quercetin. Circular dichroism spectrum analysis showed that rutin and quercetin caused similar changes in the secondary structure of proteins, both promoting β-sheet to α-helix, β-ture and random coil transformation. The fluorescence spectrometry results showed that the combination of phenols can cause the fluorescence quenching, and the combination of rutin was stronger than the quercetin. Proteomics showed that there were multiple covalent binding sites between phenols and protein. Rutin had a high affinity for arginine, and quercetin and cysteine had high affinity. Meanwhile, the combination of rutin/quercetin and protein had reduced the surface hydrophobic ability of the protein, and improved the foaming, stability and antioxidant properties of the protein. This study expounded the mechanism of the combination of BPI and rutin/quercetin, and analysed the differences of the combination of protein and phenols in different structures. The findings can provide a theoretical basis for the development of complexes in the area of food.
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Affiliation(s)
- Dongze Li
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; National Engineering Research Center for Functional Food, Jiangnan University, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, China
| | - Ling Zhu
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; National Engineering Research Center for Functional Food, Jiangnan University, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, China
| | - Qiming Wu
- Nutrilite Health Institute, Shanghai, China
| | - Yiling Chen
- Amway (China) Botanical R&D Centre, Wuxi 214115, China
| | - Gangcheng Wu
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; National Engineering Research Center for Functional Food, Jiangnan University, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, China
| | - Hui Zhang
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; National Engineering Research Center for Functional Food, Jiangnan University, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, China.
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4
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Añazco C, Riedelsberger J, Vega-Montoto L, Rojas A. Exploring the Interplay between Polyphenols and Lysyl Oxidase Enzymes for Maintaining Extracellular Matrix Homeostasis. Int J Mol Sci 2023; 24:10985. [PMID: 37446164 DOI: 10.3390/ijms241310985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/26/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023] Open
Abstract
Collagen, the most abundant structural protein found in mammals, plays a vital role as a constituent of the extracellular matrix (ECM) that surrounds cells. Collagen fibrils are strengthened through the formation of covalent cross-links, which involve complex enzymatic and non-enzymatic reactions. Lysyl oxidase (LOX) is responsible for catalyzing the oxidative deamination of lysine and hydroxylysine residues, resulting in the production of aldehydes, allysine, and hydroxyallysine. These intermediates undergo spontaneous condensation reactions, leading to the formation of immature cross-links, which are the initial step in the development of mature covalent cross-links. Additionally, non-enzymatic glycation contributes to the formation of abnormal cross-linking in collagen fibrils. During glycation, specific lysine and arginine residues in collagen are modified by reducing sugars, leading to the creation of Advanced Glycation End-products (AGEs). These AGEs have been associated with changes in the mechanical properties of collagen fibers. Interestingly, various studies have reported that plant polyphenols possess amine oxidase-like activity and can act as potent inhibitors of protein glycation. This review article focuses on compiling the literature describing polyphenols with amine oxidase-like activity and antiglycation properties. Specifically, we explore the molecular mechanisms by which specific flavonoids impact or protect the normal collagen cross-linking process. Furthermore, we discuss how these dual activities can be harnessed to generate properly cross-linked collagen molecules, thereby promoting the stabilization of highly organized collagen fibrils.
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Affiliation(s)
- Carolina Añazco
- Laboratorio de Bioquímica Nutricional, Escuela de Nutrición y Dietética, Carrera de Nutrición y Dietética, Facultad de Ciencias para el Cuidado de la Salud, Universidad San Sebastián, General Lagos #1190, Valdivia 5110773, Chile
| | - Janin Riedelsberger
- Centro de Bioinformática, Simulación y Modelado (CBSM), Facultad de Ingeniería, Universidad de Talca, 1 Poniente 1141, Talca 3462227, Chile
| | - Lorenzo Vega-Montoto
- Chemical and Radiation Measurement, Idaho National Laboratory (INL), 1705 N. Yellowstone Hwy, Idaho Falls, ID 83415, USA
| | - Armando Rojas
- Biomedical Research Laboratories, Medicine Faculty, Catholic University of Maule, Talca 3480112, Chile
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Jia Y, Yan X, Li X, Zhang S, Huang Y, Zhang D, Li Y, Qi B. Soy protein–phlorizin conjugate prepared by tyrosinase catalysis: Identification of covalent binding sites and alterations in protein structure and functionality. Food Chem 2023; 404:134610. [DOI: 10.1016/j.foodchem.2022.134610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 10/06/2022] [Accepted: 10/11/2022] [Indexed: 11/05/2022]
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Liu J, Kutateladze TG. Dietary polyphenols link extracellular histones and nonhistone proteins. J Biol Chem 2022; 298:102651. [PMID: 36377105 PMCID: PMC9667288 DOI: 10.1016/j.jbc.2022.102651] [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] [Accepted: 10/25/2022] [Indexed: 11/13/2022] Open
Abstract
Numerous studies have demonstrated antioxidant, anti-inflammatory, antimicrobial, anticancer, and cardio-protective activities of dietary polyphenols, but due to diverse structures and subclasses of polyphenols, little is known about their mechanisms of action. The study by Yamaguchi et al. published in JBC provides mechanistic insights into how dietary polyphenols confer histone-binding ability on certain proteins and motivates the research community to further explore health benefits of polyphenols.
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Affiliation(s)
- Jiuyang Liu
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Tatiana G Kutateladze
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, Colorado, USA.
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Yamaguchi K, Itakura M, Tsukamoto M, Lim SY, Uchida K. Natural polyphenols convert proteins into histone-binding ligands. J Biol Chem 2022; 298:102529. [PMID: 36162500 PMCID: PMC9589214 DOI: 10.1016/j.jbc.2022.102529] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 09/16/2022] [Accepted: 09/17/2022] [Indexed: 12/01/2022] Open
Abstract
Antioxidants are sensitive to oxidation and are immediately converted into their oxidized forms that can react with proteins. We have recently found that proteins incubated with oxidized vitamin C (dehydroascorbate) gain a new function as a histone-binding ligand. This finding led us to predict that antioxidants, through conversion to their oxidized forms, may generally have similar functions. In the present study, we identified several natural polyphenols as a source of histone ligands and characterized the mechanism for the interaction of protein-bound polyphenols with histone. Through screening of 25 plant-derived polyphenols by assessing their ability to convert bovine serum albumin into histone ligands, we identified seven polyphenols, including (-)-epigallocatechin-3-O-gallate (EGCG). Additionally, we found that the histone tail domain, which is a highly charged and conformationally flexible region, is involved in the interaction with the polyphenol-modified proteins. Further mechanistic studies showed the involvement of a complex heterogeneous group of the polyphenol-derived compounds bound to proteins as histone-binding elements. We also determined that the interaction of polyphenol-modified proteins with histones formed aggregates and exerted a protective effect against histone-mediated cytotoxicity toward endothelial cells. These findings demonstrated that histones are one of the major targets of polyphenol-modified proteins and provide important insights into the chemoprotective functions of dietary polyphenols.
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Affiliation(s)
- Kosuke Yamaguchi
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Masanori Itakura
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Mona Tsukamoto
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Sei-Young Lim
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Koji Uchida
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan; Japan Agency for Medical Research and Development, CREST, Tokyo, Japan.
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8
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Yamaguchi K, Itakura M, Kitazawa R, Lim SY, Nagata K, Shibata T, Akagawa M, Uchida K. Oxidative deamination of lysine residues by polyphenols generates an equilibrium of aldehyde and 2-piperidinol products. J Biol Chem 2021; 297:101035. [PMID: 34339739 PMCID: PMC8387773 DOI: 10.1016/j.jbc.2021.101035] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 12/04/2022] Open
Abstract
Polyphenols, especially catechol-type polyphenols, exhibit lysyl oxidase-like activity and mediate oxidative deamination of lysine residues in proteins. Previous studies have shown that polyphenol-mediated oxidative deamination of lysine residues can be associated with altered electrical properties of proteins and increased crossreactivity with natural immunoglobulin M antibodies. This interaction suggested that oxidized proteins could act as innate antigens and elicit an innate immune response. However, the structural basis for oxidatively deaminated lysine residues remains unclear. In the present study, to establish the chemistry of lysine oxidation, we characterized oxidation products obtained via incubation of the lysine analog N-biotinyl-5-aminopentylamine with eggshell membranes containing lysyl oxidase and identified a unique six-membered ring 2-piperidinol derivative equilibrated with a ring-open product (aldehyde) as the major product. By monitoring these aldehyde-2-piperidinol products, we evaluated the lysyl oxidase-like activity of polyphenols. We also observed that this reaction was mediated by some polyphenols, especially o-diphenolic-type polyphenols, in the presence of copper ions. Interestingly, the natural immunoglobulin M monoclonal antibody recognized these aldehyde-2-piperidinol products as an innate epitope. These findings establish the existence of a dynamic equilibrium of oxidized lysine and provide important insights into the chemopreventive function of dietary polyphenols for chronic diseases.
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Affiliation(s)
- Kosuke Yamaguchi
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Masanori Itakura
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Roma Kitazawa
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Sei-Young Lim
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Koji Nagata
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Takahiro Shibata
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Mitsugu Akagawa
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
| | - Koji Uchida
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan; Japan Agency for Medical Research and Development, CREST, Tokyo, Japan.
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9
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Akagawa M. Protein carbonylation: molecular mechanisms, biological implications, and analytical approaches. Free Radic Res 2021; 55:307-320. [DOI: 10.1080/10715762.2020.1851027] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Mitsugu Akagawa
- Division of Applied Life Sciences, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan
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10
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Pang XH, Yang Y, Bian X, Wang B, Ren LK, Liu LL, Yu DH, Yang J, Guo JC, Wang L, Zhang XM, Yu HS, Zhang N. Hemp ( Cannabis sativa L.) Seed Protein-EGCG Conjugates: Covalent Bonding and Functional Research. Foods 2021; 10:foods10071618. [PMID: 34359488 PMCID: PMC8304514 DOI: 10.3390/foods10071618] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 06/30/2021] [Accepted: 07/01/2021] [Indexed: 11/16/2022] Open
Abstract
In order to make HPI have a wide application prospect in the food industry, we used EGCG to modify HPI. In this study, we prepared different concentrations (1, 2, 3, 4, and 5 mM) of (-)-epigallocatechin gallate (EGCG) covalently linked to HPI and use methods such as particle size analysis, circular dichroism (CD), and three-dimensional fluorescence spectroscopy to study the changes in the structure and functional properties of HPI after being covalently combined with EGCG. The particle size data indicated that the covalent HPI-EGCG complex was larger than native HPI, and the particle size was mainly distributed at about 200 μm. CD and three-dimensional fluorescence spectroscopy analyses showed that the conformation of the protein was changed by conjugation with EGCG. The β-sheet content decreased from 82.79% to 66.67% after EGCG bound to the protein, and the hydrophobic groups inside the protein were exposed, which increased the hydrophobicity of the protein and changed its conformation. After HPI and 1 mM of EGCG were covalently bonded, the solubility and emulsifying properties of the covalent complex were improved compared with native HPI. These results indicated that HPI-EGCG conjugates can be added in some foods.
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Affiliation(s)
- Xin-Hui Pang
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Songbei District, Harbin 150076, China; (X.-H.P.); (Y.Y.); (X.B.); (B.W.); (L.-K.R.); (L.-L.L.); (D.-H.Y.); (J.Y.)
| | - Yang Yang
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Songbei District, Harbin 150076, China; (X.-H.P.); (Y.Y.); (X.B.); (B.W.); (L.-K.R.); (L.-L.L.); (D.-H.Y.); (J.Y.)
| | - Xin Bian
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Songbei District, Harbin 150076, China; (X.-H.P.); (Y.Y.); (X.B.); (B.W.); (L.-K.R.); (L.-L.L.); (D.-H.Y.); (J.Y.)
| | - Bing Wang
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Songbei District, Harbin 150076, China; (X.-H.P.); (Y.Y.); (X.B.); (B.W.); (L.-K.R.); (L.-L.L.); (D.-H.Y.); (J.Y.)
| | - Li-Kun Ren
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Songbei District, Harbin 150076, China; (X.-H.P.); (Y.Y.); (X.B.); (B.W.); (L.-K.R.); (L.-L.L.); (D.-H.Y.); (J.Y.)
| | - Lin-Lin Liu
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Songbei District, Harbin 150076, China; (X.-H.P.); (Y.Y.); (X.B.); (B.W.); (L.-K.R.); (L.-L.L.); (D.-H.Y.); (J.Y.)
| | - De-Hui Yu
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Songbei District, Harbin 150076, China; (X.-H.P.); (Y.Y.); (X.B.); (B.W.); (L.-K.R.); (L.-L.L.); (D.-H.Y.); (J.Y.)
| | - Jing Yang
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Songbei District, Harbin 150076, China; (X.-H.P.); (Y.Y.); (X.B.); (B.W.); (L.-K.R.); (L.-L.L.); (D.-H.Y.); (J.Y.)
| | - Jing-Chun Guo
- Heilongjiang Academy of Sciences, Harbin 150000, China; (J.-C.G.); (L.W.)
| | - Lei Wang
- Heilongjiang Academy of Sciences, Harbin 150000, China; (J.-C.G.); (L.W.)
| | - Xiu-Min Zhang
- Beijing Academy of Food Sciences, Beijing 100068, China;
| | - Han-Song Yu
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, China
- Division of Soybean Processing, Soybean Research & Development Center, Chinese Agricultural Research System, Changchun 130118, China
- Correspondence: (H.-S.Y.); (N.Z.)
| | - Na Zhang
- Key Laboratory of Food Science and Engineering of Heilongjiang Province, College of Food Engineering, Harbin University of Commerce, Songbei District, Harbin 150076, China; (X.-H.P.); (Y.Y.); (X.B.); (B.W.); (L.-K.R.); (L.-L.L.); (D.-H.Y.); (J.Y.)
- Correspondence: (H.-S.Y.); (N.Z.)
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Soy protein isolate -(-)-epigallocatechin gallate conjugate: Covalent binding sites identification and IgE binding ability evaluation. Food Chem 2020; 333:127400. [PMID: 32673949 DOI: 10.1016/j.foodchem.2020.127400] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 06/03/2020] [Accepted: 06/19/2020] [Indexed: 12/18/2022]
Abstract
The conjugate prepared from (-)-epigallocatechin gallate (EGCG) and soy protein isolate (SPI) under alkaline and aerobic conditions was analyzed using a Nano-LC-Q-Orbitrap-MS/MS technique. The sulfhydryl and free amino groups of SPI were involved in covalent binding. Fifty-one peptides were conjugated with EGCG. Fifty-nine modified sites were identified, located on Cys, His, Arg, and Lys, respectively. It is the first time to confirm that each of the two phenolic rings of EGCG contained a reactive site that bound to an amino acid residue. The amino acid residue reactivity, amino acid sequence and composition affected the EGCG binding site in SPI. Lys and Arg residues are the most likely sites for modification, and modification appears to reduce IgE binding. This study is helpful to elucidate the pattern of covalent binding of polyphenols to proteins in food systems and provides a theoretical basis for the directional modification of soy proteins with polyphenols.
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