1
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Lipid oxidation induced protein scission in an oleogel as a model food. Food Chem 2023; 415:135357. [PMID: 36842373 DOI: 10.1016/j.foodchem.2022.135357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 12/27/2022] [Accepted: 12/28/2022] [Indexed: 01/01/2023]
Abstract
Lipid oxidation induced protein scission was investigated in oleogel using beta-lactoglobulin (whey protein isolate) as gelator. Extracted cleaved peptides were measured using high resolution mass spectrometry (FT-ICR-MS), which was provided by an automatically generated annotation list approach to identify relevant masses and sum formula using the isotopic pattern. The identified oxidized peptides were then further evaluated using partial least squares regression to relevant lipid hydroperoxide formation data, which provide the significance and importance of the peptides toward lipid induced scission. Thereby, the most important peptides are located at the surface of the protein in random coil segments and especially at the ends of the protein sequence. The most important amino acids were cysteine and aliphatic amino acids, which undergo scission mostly by the α-amidation pathway. The findings compare well with studies investigating depletion of amino acids initiated by lipid oxidation in systems containing bovine albumin or gamma-globulin.
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2
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Zhu Y, Ding S, Wang X, Zhang R, Feng X, Sun X, Xiao G, Zhu Y. Interfacial Electronic Interaction in In 2O 3/Poly(3,4-ethylenedioxythiophene)-Modified Carbon Heterostructures for Enhanced Electroreduction of CO 2 to Formate. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37399534 DOI: 10.1021/acsami.3c05892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
Formate, as an important chemical raw material, is considered to be one of the most promising products for industrialization among CO2 electroreduction reaction (CO2RR) products, but it still suffers from poor selectivity and a low formation rate at a high current density on account of the competitory hydrogen evolution reaction. Herein, the heterogeneous nanostructure was constructed by anchoring In2O3 nanoparticles on poly(3,4-ethylenedioxythiophene) (PEDOT)-modified carbon black (In2O3/PC), in which the PEDOT polymer interface layer could immobilize In2O3 nanoparticles and obtain a notable reduction in electron transfer resistance among the In2O3 particles, showing a 27% increase in the total electron transfer rate. The optimized In2O3/PC with rich heterogeneous interfaces selectively reduced CO2 to formate with a high FE of 95.4% and a current density of 251.4 mA cm-2 under -1.18 V vs RHE. Also, the formate production rate for In2O3/PC was up to 7025.1 μmol h-1 cm-2, surpassing most previously reported CO2RR catalysts. The in situ XRD results revealed that In2O3 particles were reduced to metallic indium (In) as catalytic active sites during CO2RR. DFT calculations verified that a strong interface interaction between In sites and PC induced electron transfer from In sites to PC, which could optimize the charge distribution of active sites, accelerate electron transfer, and elevate the p-band center of In sites toward the Fermi level, thereby lowering the adsorption energy of *OCHO intermediates for CO2 conversion to formate.
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Affiliation(s)
- Ying Zhu
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, China
| | - Shaosong Ding
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, China
| | - Xingpu Wang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, China
| | - Rong Zhang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, China
| | - Xiaochen Feng
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, China
| | - Xiang Sun
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, China
| | - Guozheng Xiao
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, China
| | - Ying Zhu
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, China
- Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
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3
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Börsig A, Konar N, Dalabasmaz S. A model study on the site-specificity of (-)-epicatechin-induced reactions in β-lactoglobulin by high-resolution mass spectrometry in combination with bioinformatics. Food Chem 2023; 408:135242. [PMID: 36566544 DOI: 10.1016/j.foodchem.2022.135242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 11/23/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Polyphenol-protein reactions in model solutions of β-lactoglobulin (β-LG) incubated with (-)-epicatechin at 37 °C and 60 °C were monitored by microLC-timsTOF Pro-MS/MS combined with bioinformatics strategies. The addition of (-)-epicatechin to the model solutions resulted in changes in tryptic peptide profiles. Covalent bond formation between (-)-epicatechin o-quinones and β-LG was identified for the residues S27, S30, K60, C66, K69, and C160, with C160 being the predominant binding site. Furthermore, the incubation of β-LG with (-)-epicatechin significantly promoted oxidation, especially for the residues M7 and M24. The reaction of monomeric (-)-epicatechino-quinone at C160 was also identified in the milk chocolate sample. The adaptation of this study by extending the scope of the reaction products offers significant potential for comprehensive food profiling strategies.
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Affiliation(s)
- Amelie Börsig
- Food Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Nikolaus-Fiebiger-Straße 10, 91058 Erlangen, Germany.
| | - Nevzat Konar
- Department of Food Engineering, Eskisehir Osmangazi University, 26160 Eskisehir, Turkey.
| | - Sevim Dalabasmaz
- Food Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Nikolaus-Fiebiger-Straße 10, 91058 Erlangen, Germany.
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4
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Hoppenreijs LJG, Overbeck A, Brune SE, Biedendieck R, Kwade A, Krull R, Boom RM, Keppler JK. Amyloid-like aggregation of recombinant β-lactoglobulin at pH 3.5 and 7.0: Is disulfide bond removal the key to fibrillation? Int J Biol Macromol 2023; 242:124855. [PMID: 37187417 DOI: 10.1016/j.ijbiomac.2023.124855] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 04/19/2023] [Accepted: 05/10/2023] [Indexed: 05/17/2023]
Abstract
Functional nanofibrils from globular proteins are usually formed by heating for several hours at pH 2.0, which induces acidic hydrolysis and consecutive self-association. The functional properties of these micro-metre-long anisotropic structures are promising for biodegradable biomaterials and food applications, but their stability at pH > 2.0 is low. The results presented here show that modified β-lactoglobulin can also form nanofibrils by heating at neutral pH without prior acidic hydrolysis; the key is removing covalent disulfide bonds. The aggregation behaviour of various recombinant β-lactoglobulin variants was systemically studied at pH 3.5 and 7.0. The suppression of intra- and intermolecular disulfide bonds by eliminating one to three out of the five cysteines makes the non-covalent interactions more prevalent and allow for structural rearrangement. This stimulated the linear growth of worm-like aggregates. Full elimination of all five cysteines led to the transformation of worm-like aggregates into actual fibril structures (several hundreds of nanometres long) at pH 7.0. This understanding of the role of cysteine in protein-protein interactions will help to identify proteins and protein modifications to form functional aggregates at neutral pH.
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Affiliation(s)
- Loes J G Hoppenreijs
- Laboratory of Food Process Engineering, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands
| | - Achim Overbeck
- Technische Universität Braunschweig, Institute of Particle Technology, Volkmaroderstrasse 5, 38104 Braunschweig, Germany; Technische Universität Braunschweig, Center of Pharmaceutical Engineering (PVZ), Franz-Liszt-Straße 35a, 38106 Braunschweig, Germany
| | - Sarah E Brune
- Technische Universität Braunschweig, Institute of Biochemical Engineering, Rebenring 56, 38106 Braunschweig, Germany; Technische Universität Braunschweig, Institute of Microbiology, Rebenring 56, 38106 Braunschweig, Germany; Technische Universität Braunschweig, Braunschweig Integrated Centre of Systems Biology (BRICS), Rebenring 56, 38106 Braunschweig, Germany; Technische Universität Braunschweig, Center of Pharmaceutical Engineering (PVZ), Franz-Liszt-Straße 35a, 38106 Braunschweig, Germany
| | - Rebekka Biedendieck
- Technische Universität Braunschweig, Institute of Microbiology, Rebenring 56, 38106 Braunschweig, Germany; Technische Universität Braunschweig, Braunschweig Integrated Centre of Systems Biology (BRICS), Rebenring 56, 38106 Braunschweig, Germany
| | - Arno Kwade
- Technische Universität Braunschweig, Institute of Particle Technology, Volkmaroderstrasse 5, 38104 Braunschweig, Germany; Technische Universität Braunschweig, Center of Pharmaceutical Engineering (PVZ), Franz-Liszt-Straße 35a, 38106 Braunschweig, Germany
| | - Rainer Krull
- Technische Universität Braunschweig, Institute of Biochemical Engineering, Rebenring 56, 38106 Braunschweig, Germany; Technische Universität Braunschweig, Braunschweig Integrated Centre of Systems Biology (BRICS), Rebenring 56, 38106 Braunschweig, Germany; Technische Universität Braunschweig, Center of Pharmaceutical Engineering (PVZ), Franz-Liszt-Straße 35a, 38106 Braunschweig, Germany
| | - Remko M Boom
- Laboratory of Food Process Engineering, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands
| | - Julia K Keppler
- Laboratory of Food Process Engineering, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands.
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Qie X, Yin Z, He Z, Xue C, Wang Z, Chen Q, Zeng M, Chen J, He Z. Interaction between β-casein and phlorizin induced by thermal treatment and its effect on the antioxidant activity and bioavailability of phlorizin in vivo. FOOD BIOSCI 2023. [DOI: 10.1016/j.fbio.2023.102479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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6
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Cavalcante KN, Feitor J, Morais ST, Nassu RT, Ahrné L, Cardoso DR. Impact of UV-C pretreatment on β-lactoglobulin hydrolysis by trypsin: production and bioavailability of bioactive peptides. Int Dairy J 2023. [DOI: 10.1016/j.idairyj.2023.105650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
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Qie X, Chen W, Wu R, Wang Z, Zeng M, Chen J, Douglas Goff H, He Z. The effects of β-lactoglobulin on cyanidin-3-O-glucoside antioxidant activity and bioaccessibility after heat treatment. Food Res Int 2022; 157:111494. [PMID: 35761714 DOI: 10.1016/j.foodres.2022.111494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 05/11/2022] [Accepted: 06/07/2022] [Indexed: 11/04/2022]
Abstract
The impact of heat treatment at different temperatures on the interaction of β-lactoglobulin (β-Lg) and anthocyanin-3-O-glucoside (C3G) was studied. Heat treatment and the addition of C3G changed the secondary structure of β-Lg with decreasing β-sheets and increasing random coils. Interactions between C3G and β-Lg were mainly via hydrogen bonds and van der Waals forces at 25 °C. The elevated temperature promoted hydrophobic interactions between C3G and β-Lg due to an increase in the hydrophobic groups and amino groups on the surface of β-Lg molecules. The addition of β-Lg to the C3G eliminated heat-induced thermal degradation of C3G. The β-Lg-C3G interactions accompanied with increased particle size and constant zeta potential could increase the antioxidant capacity of C3G approximately by 4% to 10% and protect the colour of C3G from degradation under heat treatment. The C3G bioaccessibility with β-Lg addition increased by 26.08%, 33.45%, 83.09%, 72.27%, and 354.62% compared with C-25, C-60, C-85, C-100, and C-121, respectively. The protective effect of the non-covalent interactions on C3G at high temperatures (85 °C to 121 °C) was significantly stronger than at 25 °C and 60 °C. The application of β-Lg in foodstuffs could enhance the antioxidant activity and bioaccessibility of C3G.
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Affiliation(s)
- Xuejiao Qie
- State Key Laboratory of Food Science and Technoloy, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China
| | - Wenpu Chen
- State Key Laboratory of Food Science and Technoloy, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China
| | - Renyi Wu
- State Key Laboratory of Food Science and Technoloy, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China
| | - Zhaojun Wang
- State Key Laboratory of Food Science and Technoloy, Jiangnan University, Wuxi 214122, China
| | - Maomao Zeng
- State Key Laboratory of Food Science and Technoloy, Jiangnan University, Wuxi 214122, China
| | - Jie Chen
- State Key Laboratory of Food Science and Technoloy, Jiangnan University, Wuxi 214122, China
| | - H Douglas Goff
- Department of Food Science, University of Guelph, ON N1G2W1, Canada
| | - Zhiyong He
- State Key Laboratory of Food Science and Technoloy, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China.
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Li C, Engholm-Keller K, Lund MN. Site-Specific Characterization of Heat-Induced Disulfide Rearrangement in Beta-Lactoglobulin by Liquid Chromatography-Mass Spectrometry. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:847-856. [PMID: 35025507 DOI: 10.1021/acs.jafc.1c06844] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Disulfides are important for maintaining the protein native structure, but they may undergo rearrangement in the presence of free Cys residues, especially under elevated temperatures. Disulfide rearrangement may result in protein aggregation, which is associated with in vivo pathologies in organisms and in vitro protein functionality in food systems. In a food context, it is therefore important to understand the process of disulfide rearrangement on a site-specific level in order to control aggregation. In the present study, a liquid chromatography-mass spectrometry (LC-MS)-based bottom-up site-specific proteomic approach was optimized to study disulfide rearrangements in beta-lactoglobulin (β-LG) under different heat treatments (60-90 °C). Artifactual disulfide rearrangement observed during sample preparation using a conventional protocol was detected and minimized by blocking the remaining free Cys residues with iodoacetamide in the presence of urea after heat treatment. Use of endoproteinase Glu-C for enzymatic hydrolysis allowed, for the first time, identification and comparison of the relative intensity of all theoretically possible β-LG disulfide cross-links formed by the heat treatments. Non-native disulfides were formed from heat treatment at approx. 70 °C where β-LG started to unfold, while higher levels of inter-molecular disulfide links were formed at ≥80 °C, in agreement with β-LG aggregation detected by size exclusion chromatography analysis. Collectively, the Cys residues of the surface-located native disulfide Cys66-Cys160 were proposed to be more reactive, participating in heat-induced disulfide rearrangement, compared to other Cys residues. The abundant signal of non-native disulfide bonds containing Cys66, especially Cys66-Cys66, observed after heating suggested that Cys66 is a key disulfide-linked Cys residue in β-LG participating in heat-induced inter-molecular disulfide bonds and the corresponding protein aggregation.
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Affiliation(s)
- Chengkang Li
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, Frederiksberg 1958, Denmark
| | - Kasper Engholm-Keller
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, Frederiksberg 1958, Denmark
| | - Marianne N Lund
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, Frederiksberg 1958, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, Copenhagen N 2200, Denmark
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9
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He Z, Ma T, Zhang W, Su E, Cao F, Huang M, Wang Y. Heat-induced gel formation by whey protein isolate-Lycium barbarum polysaccharides at varying pHs. Food Hydrocoll 2021. [DOI: 10.1016/j.foodhyd.2021.106607] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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10
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Wang L, Ma Y, Li H, Yang F, Cheng J. Identification and characterization of yak α-lactalbumin and β-lactoglobulin. J Dairy Sci 2020; 104:2520-2528. [PMID: 33358811 DOI: 10.3168/jds.2020-18546] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 09/24/2020] [Indexed: 11/19/2022]
Abstract
α-Lactalbumin (α-LA) and β-lactoglobulin (β-LG) were isolated from yak milk and identified by mass spectrometry. The variant of α-LA (L8IIC8) in yak milk had 123 amino acids, and the sequence differed from α-LA from bovine milk. The amino acid at site 71 was Asn (N) in domestic yak milk, but Asp (D) in bovine and wild yak milk sequences. Yak β-LG had 2 variants, β-LG A (P02754) and β-LG E (L8J1Z0). Both domestic yak and wild yak milk contained β-LG E, but it was absent in bovine milk. The amino acid at site 158 of β-Lg E was Gly (G) in yak but Glu (E) in bovine. The yak α-LA and β-LG secondary structures were slightly different from those in bovine milk. The denaturation temperatures of yak α-LA and β-LG were 52.1°C and 80.9°C, respectively. This study provides insights relevant to food functionality, food safety control, and the biological properties of yak milk products.
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Affiliation(s)
- Lifeng Wang
- Food Science College, Northeast Agriculture University, Harbin 150036, China
| | - Ying Ma
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150090, China.
| | - He Li
- School of Health Sciences, Jiangsu Normal University, Xuzhou 221116, China
| | - Fuming Yang
- Food Science College, Northeast Agriculture University, Harbin 150036, China
| | - Jinju Cheng
- Food Science College, Northeast Agriculture University, Harbin 150036, China
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11
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The role of non-covalent interactions in the alkaline dissolution of heat-set whey protein hydrogels made at gelation pH 2–11. Food Hydrocoll 2019. [DOI: 10.1016/j.foodhyd.2018.10.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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12
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Ali A, Le Potier I, Huang N, Rosilio V, Cheron M, Faivre V, Turbica I, Agnely F, Mekhloufi G. Effect of high pressure homogenization on the structure and the interfacial and emulsifying properties of β-lactoglobulin. Int J Pharm 2018; 537:111-121. [DOI: 10.1016/j.ijpharm.2017.12.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 12/05/2017] [Accepted: 12/09/2017] [Indexed: 12/25/2022]
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13
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Drapala KP, Auty MA, Mulvihill DM, O'Mahony JA. Improving thermal stability of hydrolysed whey protein-based infant formula emulsions by protein–carbohydrate conjugation. Food Res Int 2016; 88:42-51. [DOI: 10.1016/j.foodres.2016.01.028] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 01/27/2016] [Accepted: 01/30/2016] [Indexed: 10/22/2022]
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14
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Krämer AC, Thulstrup PW, Lund MN, Davies MJ. Key role of cysteine residues and sulfenic acids in thermal- and H2O2-mediated modification of β-lactoglobulin. Free Radic Biol Med 2016; 97:544-555. [PMID: 27430598 DOI: 10.1016/j.freeradbiomed.2016.07.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 06/16/2016] [Accepted: 07/14/2016] [Indexed: 10/21/2022]
Abstract
Oxidation results in protein deterioration in mammals, plants, foodstuffs and pharmaceuticals, via changes in amino acid composition, fragmentation, aggregation, solubility, hydrophobicity, conformation, function and susceptibility to digestion. This study investigated whether and how individual or combined treatment with heat, a commonly encountered factor in industrial processing, and H2O2 alters the structure and composition of the major whey protein β-lactoglobulin. Thermal treatment induced reducible cross-links, with this being enhanced by low H2O2 concentrations, but decreased by high concentrations, where fragmentation was detected. Cross-linking was prevented when the single free Cys121 residue was blocked with iodoacetamide. Low concentrations of H2O2 added before heating depleted thiols, with H2O2 alone, or H2O2 added after heating, having lesser effects. A similar pattern was detected for methionine loss and methionine sulfoxide formation. Tryptophan loss was only detected with high levels of H2O2, and no other amino acid was affected, indicating that sulfur-centered amino acids are critical targets. No protection against aggregation was provided by high concentrations of the radical scavenger 5, 5-dimethyl-1-pyrroline N-oxide (DMPO), consistent with molecular oxidation, rather than radical reactions, being the major process. Sulfenic acid formation was detected by Western blotting and LC-MS/MS peptide mass-mapping of dimedone-treated protein, consistent with these species being significant intermediates in heat-induced cross-linking, especially in the presence of H2O2. Studies using circular dichroism and intrinsic fluorescence indicate that H2O2 increases unfolding during heating. These mechanistic insights provide potential strategies for modulating the extent of modification of proteins exposed to thermal and oxidant treatment.
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Affiliation(s)
- Anna C Krämer
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen 2200, Denmark
| | - Peter W Thulstrup
- Department of Chemistry, University of Copenhagen, Copenhagen 2100, Denmark
| | - Marianne N Lund
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen 2200, Denmark; Department of Food Science, University of Copenhagen, Frederiksberg 1958, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen 2200, Denmark.
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15
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Norwood EA, Chevallier M, Le Floch-Fouéré C, Schuck P, Jeantet R, Croguennec T. Heat-Induced Aggregation Properties of Whey Proteins as Affected by Storage Conditions of Whey Protein Isolate Powders. FOOD BIOPROCESS TECH 2016. [DOI: 10.1007/s11947-016-1686-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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16
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Rombouts I, Lagrain B, Scherf KA, Koehler P, Delcour JA. Formation and reshuffling of disulfide bonds in bovine serum albumin demonstrated using tandem mass spectrometry with collision-induced and electron-transfer dissociation. Sci Rep 2015; 5:12210. [PMID: 26193081 PMCID: PMC4507448 DOI: 10.1038/srep12210] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 06/18/2015] [Indexed: 12/28/2022] Open
Abstract
Thermolysin hydrolyzates of freshly isolated, extensively stored (6 years, 6 °C, dry) and heated (60 min, 90 °C, in excess water) bovine serum albumin (BSA) samples were analyzed with liquid chromatography (LC) electrospray ionization (ESI) tandem mass spectrometry (MS/MS) using alternating electron-transfer dissociation (ETD) and collision-induced dissociation (CID). The positions of disulfide bonds and free thiol groups in the different samples were compared to those deduced from the crystal structure of native BSA. Results revealed non-enzymatic posttranslational modifications of cysteine during isolation, extensive dry storage, and heating. Heat-induced extractability loss of BSA was linked to the impact of protein unfolding on the involvement of specific cysteine residues in intermolecular and intramolecular thiol-disulfide interchange and thiol oxidation reactions. The here developed approach holds promise for exploring disulfide bond formation and reshuffling in various proteins under conditions relevant for chemical, biochemical, pharmaceutical and food processing.
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Affiliation(s)
- Ine Rombouts
- Laboratory of Food Chemistry and Biochemistry, Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, box 2463, B-3001 Leuven, Belgium
| | - Bert Lagrain
- Laboratory of Food Chemistry and Biochemistry, Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, box 2463, B-3001 Leuven, Belgium
| | - Katharina A. Scherf
- Deutsche Forschungsanstalt für Lebensmittelchemie, Leibniz Institut, Lise-Meitner-Straβe 34, D-85354 Freising, Germany
| | - Peter Koehler
- Deutsche Forschungsanstalt für Lebensmittelchemie, Leibniz Institut, Lise-Meitner-Straβe 34, D-85354 Freising, Germany
| | - Jan A. Delcour
- Laboratory of Food Chemistry and Biochemistry, Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, box 2463, B-3001 Leuven, Belgium
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17
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Ruan Q, Chen Y, Kong X, Hua Y. Analysis using fluorescence labeling and mass spectrometry of disulfide-mediated interactions of soy protein when heated. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:3524-3533. [PMID: 25715170 DOI: 10.1021/jf504519z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
It is well-known that disulfide-mediated interactions are important when soy protein is heated, in which soy proteins are dissociated and rearranged to some new forms. In this study, the disulfide bond (SS) linked polymer, which was composed of the acidic (A) polypeptides of glycinin, basic (B) polypeptides of glycinin, and a small amount of α' and α of β-conglycinin, was formed as the major product, accompanied by the formation of SS-linked dimer of B and monomer of A as minor products. The role of sulfhydryl (SH) of different subunits/polypeptides for forming intermolecular SS was investigated. The SH of B in glycinin (Cys298 of G1, Cys289 of G2, Cys440 of G4) was transformed into SS in polymer identified by mass spectrometry analysis. The SH content of polymer was lower than that of glycinin and β-conglycinin subunits when heated. The SH content of B in polymer was lower than that in glycinin subunit, and both of them were decreased by heating. The SH content of A in polymer was increased and higher than that of B in polymer and A in glycinin subunit when heated. These results indicated that the SH of B in glycinin subunit was subjected to not only SH oxidation but also SH-SS exchange (with SS of A) for forming intermolecular SS of polymer. The SH oxidation and SH-SS exchange were proven by the change of SH content for the first time. The SH of B was suggested to be reactive for forming intermolecular SS of polymer.
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Affiliation(s)
- Qijun Ruan
- State Key Laboratory of Food Science and Technology and School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, Jiangsu Province, People's Republic of China
| | - Yeming Chen
- State Key Laboratory of Food Science and Technology and School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, Jiangsu Province, People's Republic of China
| | - Xiangzhen Kong
- State Key Laboratory of Food Science and Technology and School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, Jiangsu Province, People's Republic of China
| | - Yufei Hua
- State Key Laboratory of Food Science and Technology and School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, Jiangsu Province, People's Republic of China
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Wijayanti HB, Bansal N, Deeth HC. Stability of Whey Proteins during Thermal Processing: A Review. Compr Rev Food Sci Food Saf 2014. [DOI: 10.1111/1541-4337.12105] [Citation(s) in RCA: 215] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Heni B. Wijayanti
- School of Agriculture and Food Sciences; Univ. of Queensland; Brisbane QLD 4072 Australia
| | - Nidhi Bansal
- School of Agriculture and Food Sciences; Univ. of Queensland; Brisbane QLD 4072 Australia
| | - Hilton C. Deeth
- School of Agriculture and Food Sciences; Univ. of Queensland; Brisbane QLD 4072 Australia
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19
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Khan MV, Rabbani G, Ahmad E, Khan RH. Fluoroalcohols-induced modulation and amyloid formation in conalbumin. Int J Biol Macromol 2014; 70:606-14. [DOI: 10.1016/j.ijbiomac.2014.07.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 06/27/2014] [Accepted: 07/09/2014] [Indexed: 10/25/2022]
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21
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Zeiler RN, Bolhuis PG. Exposure of thiol groups in the heat-induced denaturation of β-lactoglobulin. MOLECULAR SIMULATION 2014. [DOI: 10.1080/08927022.2014.926547] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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22
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Carpineti L, Martinez MJ, Pilosof AM, Pérez OE. β-Lactoglobulin–carboxymethylcellulose core–shell microparticles: Construction, characterization and isolation. J FOOD ENG 2014. [DOI: 10.1016/j.jfoodeng.2014.01.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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23
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Cornacchia L, Forquenot de la Fortelle C, Venema P. Heat-induced aggregation of whey proteins in aqueous solutions below their isoelectric point. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:733-741. [PMID: 24364622 DOI: 10.1021/jf404456q] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Processing beverages containing high concentrations of globular proteins represents a technological challenge due to their instability during heating caused by protein aggregation and gelation. Aggregation of whey protein mixtures was investigated in aqueous model systems at pH 3.5, 4.0, and 4.5 at heating conditions resembling conventional industrial treatment (90 °C for 30 s). The extent of aggregation progressively decreased moving away from the pI. Protein aggregates became smaller and had a more open structure compared to higher pH values. Significant loss of protein dispersibility occurred at pH 4.0 and 4.5 above the denaturation T of whey protein (∼70 °C), at which aggregation was caused by intermolecular hydrophobic interactions. Accessible thiol groups were detected in the heat-treated systems, with a higher intensity at higher pH and increasing extent of aggregation. Intermolecular -S-S- bonding played only a minor role in the aggregation at all conditions studied.
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Abstract
Prevention of the heat-induced aggregation of β-lactoglobulin (β-Lg) would improve the heat stability of whey proteins. The effects of lipoic acid (LA, or thioctic acid), in both its oxidised and reduced form (dihydrolipoic acid, DHLA), on heat-induced unfolding and aggregation of β-Lg were investigated. LA/DHLA was added to native β-Lg and the mixture was heated at 70, 75, 80 or 85 °C for up to 30 min at pH 6·8. The samples were analysed by Polyacrylamide Gel Electrophoresis (PAGE) and Size-exclusion HPLC (SE-HPLC). LA was not as effective as DHLA in reducing the formation of aggregates of heated β-Lg. Heating β-Lg with DHLA resulted in formation of more β-Lg monomers (due to dissociation of native dimers) and significantly less β-Lg aggregates, compared with heating β-Lg alone. The aggregates formed in the presence of DHLA were both covalently linked, via disulphide bonds, and non-covalently (hydrophobically) linked, but the amount of covalently linked aggregates was much less than when β-Lg was heated alone. The results suggest that DHLA was able to partially trap the reactive β-Lg monomer containing a free sulphydryl (−SH) group, by forming a ‘modified monomer’, and to prevent some sulphydryl−sulphydryl and sulphydryl−disulphide interactions that lead to the formation of covalently linked protein aggregates. The effects of DHLA were similar to those of N-ethylmaleimide (NEM) and dithio(bis)-p-nitrobenzoate (DTNB). However, the advantage of using DHLA over NEM and DTNB to lessen aggregation of β-Lg is that it is a food-grade compound which occurs naturally in milk.
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25
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Gulzar M, Bouhallab S, Jardin J, Briard-Bion V, Croguennec T. Structural consequences of dry heating on alpha-lactalbumin and beta-lactoglobulin at pH 6.5. Food Res Int 2013. [DOI: 10.1016/j.foodres.2013.02.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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26
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Li L, Che L, Liang Q, Mercadé-Prieto R, Wu X, Chen XD. Study on the dissolution of heat-induced ovalbumin gel in alkaline solutions relevant to the removal of fouling deposits. J FOOD ENG 2013. [DOI: 10.1016/j.jfoodeng.2012.09.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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27
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Zeiler RNW, Bolhuis PG. Numerical study of the effect of thiol-disulfide exchange in the cluster phase of beta-lactoglobulin aggregation. Faraday Discuss 2012; 158:461-77; discussion 493-522. [PMID: 23234180 DOI: 10.1039/c2fd20030a] [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
We report a numerical study of beta-lactoglobulin aggregation using grand canonical Monte Carlo simulations of a simple lattice model in which the proteins are represented by a single lattice point and interact via a sum of a short-ranged attraction, and a long-ranged screened electrostatic repulsion. For certain values of the potential parameters we observe the so-called cluster phase, in which protein aggregates of finite size repel each other. The properties of the cluster phase are dependent on the salt concentration, the charge of the protein, and the strength of the short-ranged attraction. Disulfide bridges are modeled by covalent bonds between the lattice points, and can exchange with free thiols. Allowing the thiol-disulfide exchange leads to a severe lowering in the chemical potential of the cluster transition, or equivalently, a lower monomer density. Moreover, we find that the disulfide bridges (or the free thiol groups) are not uniformly distributed over the aggregate. The free thiol groups are significantly more abundant on the surface than in the core of the aggregate, making the surface more reactive than the inner core. This finding might explain why films made of beta-lactoglobulin by cold gelation, after resolvation, reconstitute finite aggregates rather than a monomer solution.
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Affiliation(s)
- Rosanne N W Zeiler
- van 't Hoff Institute of Molecular Sciences, Universiteit van Amsterdam, PO Box 94157, 1090 GD Amsterdam, The Netherlands
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28
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Zhang Y, Cui W, Zhang H, Dewald HD, Chen H. Electrochemistry-assisted top-down characterization of disulfide-containing proteins. Anal Chem 2012; 84:3838-42. [PMID: 22448817 DOI: 10.1021/ac300106y] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Covalent disulfide bond linkage in a protein represents an important challenge for mass spectrometry (MS)-based top-down protein structure analysis as it reduces the backbone cleavage efficiency for MS/MS dissociation. This study presents a strategy for solving this critical issue via integrating electrochemistry (EC) online with a top-down MS approach. In this approach, proteins undergo electrolytic reduction in an electrochemical cell to break disulfide bonds and then undergo online ionization into gaseous ions for analysis by electron-capture dissociation (ECD) and collision-induced dissociation (CID). The electrochemical reduction of proteins allows one to remove disulfide bond constraints and also leads to increased charge numbers of the resulting protein ions. As a result, sequence coverage was significantly enhanced, as exemplified by β-lactoglobulin A (24 vs 75 backbone cleavages before and after electrolytic reduction, respectively) and lysozyme (5 vs 66 backbone cleavages before and after electrolytic reduction, respectively). This methodology is fast and does not need chemical reductants, which would have an important impact in high-throughput proteomics research.
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Affiliation(s)
- Yun Zhang
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, United States
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29
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Nicolai T, Britten M, Schmitt C. β-Lactoglobulin and WPI aggregates: Formation, structure and applications. Food Hydrocoll 2011. [DOI: 10.1016/j.foodhyd.2011.02.006] [Citation(s) in RCA: 414] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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30
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Gulzar M, Bouhallab S, Jeantet R, Schuck P, Croguennec T. Influence of pH on the dry heat-induced denaturation/aggregation of whey proteins. Food Chem 2011. [DOI: 10.1016/j.foodchem.2011.04.037] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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31
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Reznikov G, Baars A, Delgado A. The initial stage of high-pressure induced β-lactoglobulin aggregation: the long-run simulation. Int J Food Sci Technol 2011. [DOI: 10.1111/j.1365-2621.2011.02790.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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32
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Moro A, Báez GD, Busti PA, Ballerini GA, Delorenzi NJ. Effects of heat-treated β-lactoglobulin and its aggregates on foaming properties. Food Hydrocoll 2011. [DOI: 10.1016/j.foodhyd.2010.09.021] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Ferranti P, Mamone G, Picariello G, Addeo F. The “dark side” of β-lactoglobulin: Unedited structural features suggest unexpected functions. J Chromatogr A 2011; 1218:3423-31. [DOI: 10.1016/j.chroma.2011.03.059] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 03/24/2011] [Accepted: 03/25/2011] [Indexed: 12/13/2022]
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35
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Hansted JG, Wejse PL, Bertelsen H, Otzen DE. Effect of protein-surfactant interactions on aggregation of β-lactoglobulin. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1814:713-23. [PMID: 21440683 DOI: 10.1016/j.bbapap.2011.03.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 03/16/2011] [Accepted: 03/17/2011] [Indexed: 11/26/2022]
Abstract
The milk protein β-lactoglobulin (βLG) dominates the properties of whey aggregates in food products. Here we use spectroscopic and calorimetric techniques to elucidate how anionic, cationic and non-ionic surfactants interact with bovine βLG and modulate its heat-induced aggregation. Alkyl trimethyl ammonium chlorides (xTAC) strongly promote aggregation, while sodium alkyl sulfates (SxS) and alkyl maltopyranosides (xM) reduce aggregation. Sodium dodecyl sulfate (SDS) binds to non-aggregated βLG in several steps, but reduction of aggregation was associated with the first binding step, which occurs far below the critical micelle concentration. In contrast, micellar concentrations of xMs are required to reduce aggregation. The ranking order for reduction of aggregation (normalized to their tendency to self-associate) was C10-C12>C8>C14 for SxS and C8>C10>C12>C14>C16 for xM. xTAC promote aggregation in the same ranking order as xM reduce it. We conclude that SxS reduce aggregation by stabilizing the protein's ligand-bound state (the melting temperature t(m) increases by up to 10°C) and altering its charge potential. xM monomers also stabilize the protein's ligand-bound state (increasing t(m) up to 6°C) but in the absence of charged head groups this is not sufficient by itself to prevent aggregation. Although micelles of both anionic and non-ionic surfactants destabilize βLG, they also solubilize unfolded protein monomers, leaving them unavailable for protein-protein association and thus inhibiting aggregation. Cationic surfactants promote aggregation by a combination of destabilization and charge neutralization. The food compatible surfactant sodium dodecanoate also inhibited aggregation well below the cmc, suggesting that surfactants may be a practical way to modulate whey protein properties.
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Affiliation(s)
- Jon G Hansted
- Department of Molecular Biology, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark
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36
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Xu K, Zhang Y, Tang B, Laskin J, Roach PJ, Chen H. Study of Highly Selective and Efficient Thiol Derivatization Using Selenium Reagents by Mass Spectrometry. Anal Chem 2010; 82:6926-32. [DOI: 10.1021/ac1011602] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kehua Xu
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, Key Laboratory of Molecular and Nano Probes, Ministry of Education, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, China, 250014, and Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MSIN K8-88, Richland, Washington 99352
| | - Yun Zhang
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, Key Laboratory of Molecular and Nano Probes, Ministry of Education, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, China, 250014, and Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MSIN K8-88, Richland, Washington 99352
| | - Bo Tang
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, Key Laboratory of Molecular and Nano Probes, Ministry of Education, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, China, 250014, and Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MSIN K8-88, Richland, Washington 99352
| | - Julia Laskin
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, Key Laboratory of Molecular and Nano Probes, Ministry of Education, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, China, 250014, and Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MSIN K8-88, Richland, Washington 99352
| | - Patrick J. Roach
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, Key Laboratory of Molecular and Nano Probes, Ministry of Education, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, China, 250014, and Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MSIN K8-88, Richland, Washington 99352
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, Key Laboratory of Molecular and Nano Probes, Ministry of Education, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, China, 250014, and Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MSIN K8-88, Richland, Washington 99352
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37
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Krebs MR, Devlin GL, Donald AM. Amyloid fibril-like structure underlies the aggregate structure across the pH range for beta-lactoglobulin. Biophys J 2009; 96:5013-9. [PMID: 19527661 PMCID: PMC2712037 DOI: 10.1016/j.bpj.2009.03.028] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 02/05/2009] [Accepted: 03/17/2009] [Indexed: 11/22/2022] Open
Abstract
The protein beta-lactoglobulin aggregates into two apparently distinct forms under different conditions: amyloid fibrils at pH values away from the isoelectric point, and spherical aggregates near it. To understand this apparent dichotomy in behavior, we studied the internal structure of the spherical aggregates by employing a range of biophysical approaches. Fourier transform infrared studies show the aggregates have a high beta-sheet content that is distinct from the native beta-lactoglobulin structure. The structures also bind the amyloidophilic dye thioflavin-T, and wide-angle x-ray diffraction showed reflections corresponding to spacings typically observed for amyloid fibrils composed of beta-lactoglobulin. Combined with small-angle x-ray scattering data indicating the presence of one-dimensional linear aggregates at the molecular level, these findings indicate strongly that the aggregates contain amyloid-like substructure. Incubation of beta-lactoglobulin at pH values increasingly removed from the isoelectric point resulted in the increasing appearance of fibrillar species, rather than spherical species shown by electron microscopy. Taken together, these results suggest that amyloid-like beta-sheet structures underlie protein aggregation over a much broader range of conditions than previously believed. Furthermore, the results suggest that there is a continuum of beta-sheet structure of varying regularity underlying the aggregate morphology, from very regular amyloid fibrils at high charge to short stretches of amyloid-like fibrils that associate together randomly to form spherical particles at low net charge.
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Affiliation(s)
| | | | - Athene M. Donald
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
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38
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Donato L, Schmitt C, Bovetto L, Rouvet M. Mechanism of formation of stable heat-induced β-lactoglobulin microgels. Int Dairy J 2009. [DOI: 10.1016/j.idairyj.2008.11.005] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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39
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Donato L, Guyomarc'h F. Formation and properties of the whey protein/κ-casein complexes in heated skim milk – A review. ACTA ACUST UNITED AC 2009. [DOI: 10.1051/dst:2008033] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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40
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41
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Jung JM, Savin G, Pouzot M, Schmitt C, Mezzenga R. Structure of Heat-Induced β-Lactoglobulin Aggregates and their Complexes with Sodium-Dodecyl Sulfate. Biomacromolecules 2008; 9:2477-86. [DOI: 10.1021/bm800502j] [Citation(s) in RCA: 250] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jin-Mi Jung
- Department of Physics, University of Fribourg, Perolles, Fribourg, CH-1700, Switzerland, and Department of Food Science and Technology, Nestlé Research Center, Vers-Chez-Les-Blanc, Lausanne 26, CH-1000, Switzerland
| | - Gabriela Savin
- Department of Physics, University of Fribourg, Perolles, Fribourg, CH-1700, Switzerland, and Department of Food Science and Technology, Nestlé Research Center, Vers-Chez-Les-Blanc, Lausanne 26, CH-1000, Switzerland
| | - Matthieu Pouzot
- Department of Physics, University of Fribourg, Perolles, Fribourg, CH-1700, Switzerland, and Department of Food Science and Technology, Nestlé Research Center, Vers-Chez-Les-Blanc, Lausanne 26, CH-1000, Switzerland
| | - Christophe Schmitt
- Department of Physics, University of Fribourg, Perolles, Fribourg, CH-1700, Switzerland, and Department of Food Science and Technology, Nestlé Research Center, Vers-Chez-Les-Blanc, Lausanne 26, CH-1000, Switzerland
| | - Raffaele Mezzenga
- Department of Physics, University of Fribourg, Perolles, Fribourg, CH-1700, Switzerland, and Department of Food Science and Technology, Nestlé Research Center, Vers-Chez-Les-Blanc, Lausanne 26, CH-1000, Switzerland
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Abstract
β-lactoglobulin is a protein of huge importance to the food industry, and as such it has been extensively studied by the food community sui generis. However, recently there has been an increasing number of studies approaching the protein from a soft matter perspective. Here it is shown how its behaviour can be seen to be generic, in so far as its forms of aggregation are actually typical of many other proteins under comparable conditions, and hence that it is useful to seek unifying mechanisms for its behaviour.
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Affiliation(s)
- Athene M Donald
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge, UKCB3 0HE
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44
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Seiwert B, Hayen H, Karst U. Differential labeling of free and disulfide-bound thiol functions in proteins. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2008; 19:1-7. [PMID: 17977013 DOI: 10.1016/j.jasms.2007.10.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 09/26/2007] [Accepted: 10/01/2007] [Indexed: 05/25/2023]
Abstract
A method for the simultaneous determination of the number of free cysteine groups and disulfide-bound cysteine groups in proteins has been developed based on the sequential labeling of free and bound thiol functionalities with two ferrocene-based maleimide reagents. Liquid chromatography/electrochemistry/mass spectrometry was used to assign the N-(2-ferroceneethyl)maleimide (FEM) labeled free cysteine functionalities in a tryptic digest mixture, whereas a precursor ion scan enables the detection of peptides with ferrocenecarboxylic acid-(2-maleimidoyl)ethylamide (FMEA) labeled disulfide-bound cysteine groups after reduction. Fragment spectra of the labeled peptides yield an excellent coverage of b-type and y-type ions. The ferrocene labeled cysteines were fragmented as 412 Da (FEM) and 455 Da (FMEA). These fragment masses are significantly higher than unlabeled amino acids or dipeptides and are easily detected. The position of free and disulfide-bound cysteine may therefore be assigned in an amino acid sequence.
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Affiliation(s)
- Bettina Seiwert
- Chemical Analysis Group and MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands
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45
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Kehoe JJ, Brodkorb A, Mollé D, Yokoyama E, Famelart MH, Bouhallab S, Morris ER, Croguennec T. Determination of exposed sulfhydryl groups in heated beta-lactoglobulin A using IAEDANS and mass spectrometry. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2007; 55:7107-13. [PMID: 17650000 DOI: 10.1021/jf070397r] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
This paper takes a new approach to determining which sulfhydryl groups are exposed during the heat denaturation of bovine beta-lactoglobulin A. The sulfhydryl groups exposed after heating were blocked with 5-((((2-iodoacetyl)amino)ethyl)amino)naphthalene-1-sulfonic acid (IAEDANS). The results show that IAEDANS is a suitable blocking agent, and its absorbance at 336 nm enabled the quantification of exposed sulfhydryl groups in a mixture of protein species by gel permeation chromatography. Combined with the specific fragmentation of bound IAEDANS by matrix-assisted laser desorption ionization (MALDI) MS/MS in negative ionization mode, this facilitated the identification of peptides that contained blocked cysteines after enzymatic digestion of the protein. During MALDI MS/MS of the peptides, in positive ionization mode, the IAEDANS molecule remained bound to the cysteines, making it possible to identify exactly which cysteine had been exposed after heating. In beta-lactoglobulin A it was found that cysteine 66 and cysteine 160 were predominantly exposed regardless of the length of exposure to heat.
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Affiliation(s)
- Joseph J Kehoe
- Moorepark Food Research Centre, Teagasc, Fermoy, County Cork, Ireland
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Abstract
Heating is necessary for processing milk in the dairy industry, which evidently produces a conformational change in beta-lactoglobulin (beta-LG). beta-Lactoglobulin, a major protein that accounts for approximately 10 to 15% of total milk proteins, is a globular protein consisting of 162 AA with a relative molecular mass of 18.4 kDa. The purpose of the present study was to determine the antioxidant role of beta-LG in milk and the possible mechanism involved. We showed that beta-LG is a mild antioxidant whose potency is less than that of vitamin E and probucol (the latter being an antioxidant used for clinical therapy). The conversion of the beta-LG monomer to dimer was responsible, in part, for the mode of action in protecting low-density lipoproteins against copper-induced oxidation. Cross-linking the free thiol groups of beta-LG by heating (100 degrees C for 2 min), or chemically modifying the beta-LG by carboxymethylation to block the thiol groups resulted in a substantial loss of antioxidant activity. The data suggest that Cys-121 plays an essential role in the antioxidant nature of beta-LG. By using an anti-LG antibody affinity column to deplete the beta-LG from milk, we observed from the lost antioxidant activity that beta-LG contributes approximately 50% of the total activity. Because beta-LG is extremely sensitive to thermal denaturation, to maintain its antioxidant nature, dairy products consumed daily should not be overheated in order to maintain its antioxidant nature.
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Affiliation(s)
- H C Liu
- Department of Biological Science and Technology, College of Biological Science and Technology, National Chiao Tung University, Taiwan, Republic of China
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47
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Broersen K, Elshof M, De Groot J, Voragen AGJ, Hamer RJ, De Jongh HHJ. Aggregation of beta-lactoglobulin regulated by glucosylation. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2007; 55:2431-7. [PMID: 17326655 DOI: 10.1021/jf063178z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
A large number of proteins are glycosylated, either in vivo or as a result of industrial processing. Even though the effect of glycosylation on the aggregation of proteins has been studied extensively in the past, some reports show that the aggregation process is accelerated, whereas others found that the process is inhibited by glycosylation. This paper investigates the reasons behind these controversial results as well as the potential mechanism of the effect of glucosylation on aggregation using bovine beta-lactoglobulin as a model. Glucosylation was found to inhibit denaturant-induced aggregation, whereas heat-induced aggregation was accelerated. It was also found that the kinetic partitioning from an unfolded state was driven toward refolding for glucosylated protein, whereas aggregation was the preferred route for the nonglucosylated protein.
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Affiliation(s)
- Kerensa Broersen
- Wageningen Centre for Food Sciences, Diedenweg 20, P.O. Box 557, 6700 AN Wageningen, The Netherlands.
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48
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Interactions of milk proteins during heat and high hydrostatic pressure treatments — A Review. INNOV FOOD SCI EMERG 2007. [DOI: 10.1016/j.ifset.2006.08.003] [Citation(s) in RCA: 250] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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49
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Abstract
Protein aggregation is a problem with a multitude of consequences, ranging from affecting protein expression to its implication in many diseases. Of recent interest is the specific form of aggregation leading to the formation of amyloid fibrils, structures associated with diseases such as Alzheimer's disease. The ability to form amyloid fibrils is now regarded as a property generic to all polypeptide chains. Here we show that around the isoelectric point a different generic form of aggregation can also occur by studying seven widely different, nonrelated proteins that are also all known to form amyloid fibrils. Under these conditions gels consisting of relatively monodisperse spherical particulates are formed. Although these gels have been described before for beta-lactoglobulin, our results suggest that the formation of particulates in the regime where charge on the molecules is minimal is a common property of all proteins. Because the proteins used here also form amyloid fibrils, we further propose that protein misfolding into clearly defined aggregates is a generic process whose outcome depends solely on the general properties of the state the protein is in when aggregation occurs, rather than the specific amino acid sequence. Thus under conditions of high net charge, amyloid fibrils form, whereas under conditions of low net charge, particulates form. This observation furthermore suggests that the rules of soft matter physics apply to these systems.
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Affiliation(s)
- Mark R H Krebs
- Sector of Biological and Soft Systems, Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom.
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50
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Majhi PR, Ganta RR, Vanam RP, Seyrek E, Giger K, Dubin PL. Electrostatically driven protein aggregation: beta-lactoglobulin at low ionic strength. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:9150-9. [PMID: 17042523 DOI: 10.1021/la053528w] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The aggregation of beta-lactoglobulin (BLG) at ambient temperature was studied using turbidimetry and dynamic light scattering in the range 3.8<pH<5.2 in 0.0045 M NaCl, and in the ionic strength range 0.0045-0.5 M at fixed pH=5.0. The initial rate of aggregation, taken as the initial slope of turbidity vs time, (dtau/dt)0, indicated maximum aggregation near pH 4.6 (below the isoelectric point of 5.2), but the dependence of the initial rate of aggregation on pH was highly asymmetric. At pH 5.0, (dtau/dt)0 strongly increased with a decrease in ionic strength I from 0.1 to 0.0045 M and was found to be nearly linear with 1/I. DLS measurements revealed an increase in particle size with time, with the appearance of bimodal distributions in which the fast and slow modes corresponded, respectively, to a BLG dimer and to larger aggregates in the 100-800 nm range. At conditions of slower aggregation, DLS revealed the consumption of dimers to form higher order aggregates with no intermediate species. Computer modeling (Delphi) was used to visualize the electrostatic potential around the dimer to elucidate the pH and ionic strength dependence of the initial aggregation rates. The aggregation process appears to comprise an initial fast consumption of the dimer, whose dependence on pH and I arises from the interaction of the positive and negative domains of interacting dimers, followed by the slow formation of much larger aggregates with relatively little sensitivity to pH and I. The open-ended nature of BLG aggregation is thought to arise from the asymmetry of the dimer charge distribution.
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Affiliation(s)
- Pinaki R Majhi
- Department of Chemistry, Indiana University-Purdue University at Indianapolis, 402 North Blackford Street, Indianapolis, Indiana 46202, USA
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