1
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Feng J, Huang Z, Cui C, Zhao M, Feng Y. Synthesis, taste characteristics and taste mechanism of N-lactoyl leucine from soy sauce using sensory analysis and UPLC-MS/MS. Food Chem 2024; 454:139670. [PMID: 38820630 DOI: 10.1016/j.foodchem.2024.139670] [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: 02/22/2024] [Revised: 04/19/2024] [Accepted: 05/13/2024] [Indexed: 06/02/2024]
Abstract
Recently, amino acid derivatives gradually gained attention, but studies on N-lactoyl-leucine (Lac-Leu) and N-lactoyl-isoleucine (Lac-Ile) are limited. This study aims to explore the contributions of Lac-Leu and Lac-Ile to soy sauce. Lac-Leu and Lac-Ile were synthesized via enzymatic synthesis method catalyzed by Tgase. The mixed solutions containing Lac-Leu were found to have greater taste improvement than those containing Lac-Ile. Sensory evaluation indicated the sour, bitter, and astringent taste of Lac-Leu in water as well as its kokumi, astringent, and umami-enhancing taste in MSG solution. The taste threshold and umami-enhancing threshold of Lac-Leu measured by TDA and cTDA, respectively, were 0.08 mg/mL and 0.16 mg/mL. Molecular docking of Lac-Leu and Lac-Ile with the kokumi receptor CaSR and the umami receptors T1R1 and T1R3 indicated that Lac-Leu had higher affinities with receptors than Lac-Ile. These findings demonstrated the underlying contribution Lac-Leu made to soy sauce, indicating its potential to improve the flavor quality of soy sauce.
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Affiliation(s)
- Junwei Feng
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China; Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou 510650, China
| | - Zikun Huang
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China; Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou 510650, China
| | - Chun Cui
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Mouming Zhao
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China; Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou 510650, China
| | - Yunzi Feng
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China; Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou 510650, China.
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2
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Huang Z, Feng Y, Zeng J, Zhao M. Six categories of amino acid derivatives with potential taste contributions: a review of studies on soy sauce. Crit Rev Food Sci Nutr 2023; 64:7981-7992. [PMID: 37009850 DOI: 10.1080/10408398.2023.2194422] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
Abstract
During the fermentation of soy sauce, the metabolism of microorganisms and the Maillard reaction produce a wide variety of metabolites that contribute to the unique and rich flavor characteristics of soy sauce, such as amino acids, organic acids and peptides. Amino acid derivatives, a relatively new taste compounds, formed by the reaction of enzymes or non-enzymes from sugars, amino acids, and organic acids released through metabolism by microorganisms during soy sauce fermentation, have begun to gain more and more attention in recent years. This review focused on our existing knowledge of the sources, taste characteristics and synthesis methods of the 6 categories of amino acid derivatives, including Amadori compounds, γ-glutamyl peptides, pyroglutamyl amino acids, N-lactoyl amino acids, N-acetyl amino acids and N-succinyl amino acids. Sixty-four amino acid derivatives were detected in soy sauce, of which 47 were confirmed to have potential contribution to the taste of soy sauce, especially umami and kokumi, and some of them also have the effect of reducing bitterness. Furthermore, some amino acid derivatives, like γ-glutamyl peptides and N-lactoyl amino acids, were found to be synthesized enzymatically in vitro, which laid the foundation for further study on their formation pathways in the future.
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Affiliation(s)
- Zikun Huang
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
- Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou, China
| | - Yunzi Feng
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
- Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou, China
| | - Jing Zeng
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
- Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou, China
| | - Mouming Zhao
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
- Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou, China
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3
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Zhu W, He W, Wang F, Bu Y, Li X, Li J. Prediction, molecular docking and identification of novel umami hexapeptides derived from Atlantic cod (
Gadus morhua
). Int J Food Sci Technol 2021. [DOI: 10.1111/ijfs.14655] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Wenhui Zhu
- College of Food Science and Engineering Bohai University Jinzhou Liaoning 121013 China
- National & Local Joint Engineering Research Center of Storage Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products Jinzhou Liaoning 121013 China
- The Fresh Food Storage and Processing Technology Research Institute of Liaoning Provincial Universities Jinzhou Liaoning 121013 China
| | - Wei He
- College of Food Science and Engineering Bohai University Jinzhou Liaoning 121013 China
- National & Local Joint Engineering Research Center of Storage Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products Jinzhou Liaoning 121013 China
- The Fresh Food Storage and Processing Technology Research Institute of Liaoning Provincial Universities Jinzhou Liaoning 121013 China
| | - Fei Wang
- College of Food Science and Engineering Bohai University Jinzhou Liaoning 121013 China
- National & Local Joint Engineering Research Center of Storage Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products Jinzhou Liaoning 121013 China
- The Fresh Food Storage and Processing Technology Research Institute of Liaoning Provincial Universities Jinzhou Liaoning 121013 China
| | - Ying Bu
- College of Food Science and Engineering Bohai University Jinzhou Liaoning 121013 China
- National & Local Joint Engineering Research Center of Storage Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products Jinzhou Liaoning 121013 China
- The Fresh Food Storage and Processing Technology Research Institute of Liaoning Provincial Universities Jinzhou Liaoning 121013 China
| | - Xuepeng Li
- College of Food Science and Engineering Bohai University Jinzhou Liaoning 121013 China
- National & Local Joint Engineering Research Center of Storage Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products Jinzhou Liaoning 121013 China
- The Fresh Food Storage and Processing Technology Research Institute of Liaoning Provincial Universities Jinzhou Liaoning 121013 China
| | - Jianrong Li
- College of Food Science and Engineering Bohai University Jinzhou Liaoning 121013 China
- National & Local Joint Engineering Research Center of Storage Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products Jinzhou Liaoning 121013 China
- The Fresh Food Storage and Processing Technology Research Institute of Liaoning Provincial Universities Jinzhou Liaoning 121013 China
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4
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Yu Z, Kang L, Zhao W, Wu S, Ding L, Zheng F, Liu J, Li J. Identification of novel umami peptides from myosin via homology modeling and molecular docking. Food Chem 2020; 344:128728. [PMID: 33272753 DOI: 10.1016/j.foodchem.2020.128728] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 11/17/2020] [Accepted: 11/21/2020] [Indexed: 02/03/2023]
Abstract
The structure of the umami receptor T1R1/T1R3 was constructed using homology modeling and molecular dynamics, and the interactions between peptides and this umami receptor were studied by molecular docking. The umami intensity of the peptides was also investigated by using an electronic tongue. The results showed that 99.3% of the amino acid residues in the homologous model of the T1R1/T1R3 heterodimer were within the allowable range, which is greater than the threshold requirement of 90% of the residues in the high-quality model structure. Five novel peptides (DK, EEK, EDQK, SEGGR, and QDSIGS) were selected and synthesized. The umami intensity of these five peptides was stronger than that of monosodium glutamate. The docking results revealed that the interactions between peptides and the major amino acids residues Arg151, Asp147, and Gln52 of T1R1 play critical roles in the production of umami taste.
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Affiliation(s)
- Zhipeng Yu
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, PR China; Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University (BTBU), Beijing 102488, PR China
| | - Lixin Kang
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, PR China
| | - Wenzhu Zhao
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, PR China.
| | - Sijia Wu
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, PR China
| | - Long Ding
- College of Food Science and Engineering, Northwest A&F University, Yangling 712100, PR China
| | - Fuping Zheng
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University (BTBU), Beijing 102488, PR China
| | - Jingbo Liu
- Lab of Nutrition and Functional Food, Jilin University, Changchun 130062, PR China.
| | - Jianrong Li
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, PR China.
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5
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Ehrengruber MU, Lundstrom K. Recombinant Alphavirus-Mediated Expression of Ion Channels and Receptors in the Brain. NEUROMETHODS 2016. [DOI: 10.1007/978-1-4939-3064-7_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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6
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Dang Y, Gao X, Xie A, Wu X, Ma F. Interaction Between Umami Peptide and Taste Receptor T1R1/T1R3. Cell Biochem Biophys 2014; 70:1841-8. [DOI: 10.1007/s12013-014-0141-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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7
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Selective actions of novel allosteric modulators reveal functional heteromers of metabotropic glutamate receptors in the CNS. J Neurosci 2014; 34:79-94. [PMID: 24381270 DOI: 10.1523/jneurosci.1129-13.2014] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Metabotropic glutamate (mGlu) receptors play important roles in regulating CNS function and are known to function as obligatory dimers. Although recent studies have suggested heterodimeric assembly of mGlu receptors in vitro, the demonstration that distinct mGlu receptor proteins can form heterodimers or hetero-complexes with other mGlu subunits in native tissues, such as neurons, has not been shown. Using biochemical and pharmacological approaches, we demonstrate here that mGlu2 and mGlu4 form a hetero-complex in native rat and mouse tissues which exhibits a distinct pharmacological profile. These data greatly extend our current understanding of mGlu receptor interaction and function and provide compelling evidence that mGlu receptors can function as heteromers in intact brain circuits.
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8
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Hinoi E, Yoneda Y. [Glutamate signaling in non-neuronal tissues]. Nihon Yakurigaku Zasshi 2012; 139:165-9. [PMID: 22498681 DOI: 10.1254/fpj.139.165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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9
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Nakashima K, Eddy MC, Katsukawa H, Delay ER, Ninomiya Y. Behavioral responses to glutamate receptor agonists and antagonists implicate the involvement of brain-expressed mGluR4 and mGluR1 in taste transduction for umami in mice. Physiol Behav 2012; 105:709-19. [DOI: 10.1016/j.physbeh.2011.09.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2011] [Revised: 09/09/2011] [Accepted: 09/30/2011] [Indexed: 11/15/2022]
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10
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McCool BA, Chappell AM. Using monosodium glutamate to initiate ethanol self-administration in inbred mouse strains. Addict Biol 2012; 17:121-31. [PMID: 21054690 DOI: 10.1111/j.1369-1600.2010.00260.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Voluntary oral ethanol consumption in rodents is generally limited by strong taste-aversion in these species. Historically, this has been overcome by combining ethanol with a sweetener, typically sucrose or saccharine, and then slowly 'fading' away the sweetener. While useful in most instances, this approach has not proven as successful for some inbred strains of mice (e.g. DBA/2J) despite consistent evidence in the literature that these same strains express strong conditioned place preference for intraperitoneal- or intragastric-administered ethanol. Importantly, DBA/2J mice express a polymorphism in a 'sweet' taste receptor subunit gene that reduces the potency of sweet substances in these mice. We hypothesized that the presence of this polymorphism might help explain the contrasting behavioral findings of weak voluntary oral ethanol consumption following sucrose-fade yet robust conditioned place preference for ethanol in this strain. To test this, we compared ethanol consumption initiated by either a 'traditional' sucrose-fade or a fade from an alternative tastant, monosodium glutamate (MSG). We found that in both C57BL/6J and DBA/2J mice, the MSG-fade produced robust increases in home cage ethanol consumption relative to the traditional sucrose-fade. This increased ethanol intake following MSG-fade was evident across a range of ethanol concentrations. Our findings suggest the potential utility of the MSG-fade to establish stable voluntary oral ethanol consumption in mice, particularly ethanol 'non-preferring' strains such as DBA/2J and lend additional support to the notion that ethanol consumption in DBA/2J mice is limited by pronounced taste aversion.
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Affiliation(s)
- Brian A McCool
- Translational Center for the Neurobehavioral Study on Alcohol, Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
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11
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Abstract
Radioligand binding is widely used to characterize receptors and determine their anatomical distribution, particularly the superfamily of seven transmembrane-spanning G protein-coupled receptors for both established transmitters such as endothelin-1 and an increasing number of orphan receptors recently paired with their cognate ligands. Three types of assay are described. In saturation experiments, tissue sections, cultured cells, or homogenates are incubated with an increasing concentration of a radiolabeled ligand, which can be a labeled analog of a naturally occurring transmitter, hormone, or synthetic drug. Analysis using iterative nonlinear curve-fitting programs, such as KELL, measures the affinity of the labeled ligand for a receptor (equilibrium dissociation constant, K ( D )), receptor density (B (max)), and Hill slope (nH). The affinity and selectivity of an unlabeled ligand to compete for the binding of a fixed concentration of a radiolabeled ligand to a receptor are determined using a competition binding assay. Kinetic assays measure the rate of association to or dissociation from a receptor from which a kinetic K ( D ) may be derived. Quantitative autoradiography and image analysis is a sensitive technique to detect low levels of radiolabeled ligands and determine the anatomical distribution of receptors in sections that retain the morphology of the tissue. The measurement of bound radioligand within discrete regions of autoradiographical images using -computer-assisted image analysis is described.
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Affiliation(s)
- Janet J Maguire
- Clinical Pharmacology Unit, Addenbrooke's Centre for Clinical Investigation, University of Cambridge, Cambridge, UK.
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12
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Filosa R, Marinozzi M, Costantino G, Hermit MB, Thomsen C, Pellicciari R. Synthesis and biological evaluation of (2S)- and (2R)-2-(3'-phosphonobicyclo[1.1.1]pentyl)glycines as novel group III selective metabotropic glutamate receptor ligands. Bioorg Med Chem 2006; 14:3811-7. [PMID: 16460952 DOI: 10.1016/j.bmc.2006.01.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2005] [Revised: 01/10/2006] [Accepted: 01/17/2006] [Indexed: 11/20/2022]
Abstract
The synthesis of (2S)- and (2R)-2-(3'-phosphonobicyclo[1.1.1]pentyl)glycine isomers (10 and 11), characterized by the bioisosteric replacement of the distal carboxylic group of 2-(3'-carboxybicyclo[1.1.1]pent-1-yl)glycine by the phosphonate moiety, was accomplished by a stereoselective Ugi condensation. The two isomers were tested for their activity against an array of metabotropic glutamate receptors, and the S-isomer (10) turned out to be a moderately potent and selective mGluR4 agonist.
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Affiliation(s)
- Rosanna Filosa
- Dipartimento di Chimica e Tecnologia del Farmaco, Università di Perugia, Via del Liceo, 1- 06123 Perugia, Italy
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13
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He W, Yasumatsu K, Varadarajan V, Yamada A, Lem J, Ninomiya Y, Margolskee RF, Damak S. Umami taste responses are mediated by alpha-transducin and alpha-gustducin. J Neurosci 2005; 24:7674-80. [PMID: 15342734 PMCID: PMC6729622 DOI: 10.1523/jneurosci.2441-04.2004] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The sense of taste comprises at least five distinct qualities: sweet, bitter, sour, salty, and umami, the taste of glutamate. For bitter, sweet, and umami compounds, taste signaling is initiated by binding of tastants to G-protein-coupled receptors in specialized epithelial cells located in the taste buds, leading to the activation of signal transduction cascades. Alpha-gustducin, a taste cell-expressed G-protein alpha subunit closely related to the alpha-transducins, is a key mediator of sweet and bitter tastes. Alpha-gustducin knock-out (KO) mice have greatly diminished, but not entirely abolished, responses to many bitter and sweet compounds. We set out to determine whether alpha-gustducin also mediates umami taste and whether rod alpha-transducin (alpha(t-rod)), which is also expressed in taste receptor cells, plays a role in any of the taste responses that remain in alpha-gustducin KO mice. Behavioral tests and taste nerve recordings of single and double KO mice lacking alpha-gustducin and/or alpha(t-rod) confirmed the involvement of alpha-gustducin in bitter (quinine and denatonium) and sweet (sucrose and SC45647) taste and demonstrated the involvement of alpha-gustducin in umami [monosodium glutamate (MSG), monopotassium glutamate (MPG), and inosine monophosphate (IMP)] taste as well. We found that alpha(t-rod) played no role in taste responses to the salty, bitter, and sweet compounds tested or to IMP but was involved in the umami taste of MSG and MPG. Umami detection involving alpha-gustducin and alpha(t-rod) occurs in anteriorly placed taste buds, however taste cells at the back of the tongue respond to umami compounds independently of these two G-protein subunits.
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Affiliation(s)
- Wei He
- Department of Physiology and Biophysics, The Mount Sinai School of Medicine, New York, New York 10029, USA
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14
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Hermit MB, Greenwood JR, Bräuner-Osborne H. Mutation-induced quisqualic acid and ibotenic acid affinity at the metabotropic glutamate receptor subtype 4: ligand selectivity results from a synergy of several amino acid residues. J Biol Chem 2004; 279:34811-7. [PMID: 15184361 DOI: 10.1074/jbc.m404109200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The metabotropic glutamate receptors (mGluRs) are key modulators of excitatory neurotransmission in the central nervous system. The eight mGluR subtypes are seven trans-membrane-spanning proteins that possess a large extracellular amino-terminal domain in which the endogenous ligand binding pocket resides. In this study, we have identified four non-conserved amino acid residues that are essential for differentiating mGluR1 from mGluR4. Our approach has been to increase the affinity of the classic mGluR1 agonists, quisqualic acid and ibotenic acid, at mGluR4 by making various point mutations that mimicked mGluR1 residues. Based on ligand docking to homology models, the non-conserved residues, Lys-74, Glu-287, Ser-313, and Lys-317, were chosen for the mutational studies and all of the mutations proved capable of partially or completely restoring the affinities of the ligands. In particular, the mutations K74Y and K317R induced dramatic triple-order-of-magnitude increases in the affinity of ibotenic acid at mGluR4, making the affinity equivalent to that of mGluR1. Furthermore, the affinity of quisqualic acid at mGluR4 was increased to the same level as mGluR1 by the two double mutations, K74Y/K317R and K74Y/E287G. Advanced analysis of ligand conformation and docking procedures were used for the interpretation of these results. The study shows that mGluR subtype selectivity results from a complex interplay of residues shaping the binding pocket, rather than being attributable to a single specific ligand-receptor interaction.
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Affiliation(s)
- Mette B Hermit
- Department of Medicinal Chemistry, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK-2100 Copenhagen, Denmark
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15
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Hermit MB, Greenwood JR, Nielsen B, Bunch L, Jørgensen CG, Vestergaard HT, Stensbøl TB, Sanchez C, Krogsgaard-Larsen P, Madsen U, Bräuner-Osborne H. Ibotenic acid and thioibotenic acid: a remarkable difference in activity at group III metabotropic glutamate receptors. Eur J Pharmacol 2004; 486:241-50. [PMID: 14985045 DOI: 10.1016/j.ejphar.2003.12.033] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2003] [Revised: 12/15/2003] [Accepted: 12/23/2003] [Indexed: 10/26/2022]
Abstract
In this study, we have determined and compared the pharmacological profiles of ibotenic acid and its isothiazole analogue thioibotenic acid at native rat ionotropic glutamate (iGlu) receptors and at recombinant rat metabotropic glutamate (mGlu) receptors expressed in mammalian cell lines. Thioibotenic acid has a distinct pharmacological profile at group III mGlu receptors compared with the closely structurally related ibotenic acid; the former is a potent (low microm) agonist, whereas the latter is inactive. By comparing the conformational energy profiles of ibotenic and thioibotenic acid with the conformations preferred by the ligands upon docking to mGlu1 and models of the other mGlu subtypes, we propose that unlike other subtypes, group III mGlu receptor binding sites require a ligand conformation at an energy level which is prohibitively expensive for ibotenic acid, but not for thioibotenic acid. These studies demonstrate how subtle differences in chemical structures can result in profound differences in pharmacological activity.
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Affiliation(s)
- Mette B Hermit
- Department of Medicinal Chemistry, The Danish University of Pharmaceutical Sciences, 2 Universitetsparken, Copenhagen, DK-2100, Denmark
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16
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Beksan E, Schieberle P, Robert F, Blank I, Fay LB, Schlichtherle-Cerny H, Hofmann T. Synthesis and sensory characterization of novel umami-tasting glutamate glycoconjugates. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2003; 51:5428-5436. [PMID: 12926893 DOI: 10.1021/jf0344441] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Two glycoconjugates of glutamic acid, namely, the N-glycoside dipotassium N-(d-glucos-1-yl)-l-glutamate (1) and the corresponding Amadori compound N-(1-deoxy-d-fructos-1-yl)-l-glutamic acid (2), have been synthesized in yields of 35 and 52%, respectively, using new Maillard-mimetic approaches, and their chemical structures have unequivocally been elucidated by 1D- and 2D-NMR and MS experiments. Systematic sensory studies revealed that both glycoconjugates exhibit pronounced umami-like taste with recognition taste thresholds of 1-2 mmol/L, close to that of monosodium glutamate (MSG). Contrary to an aqueous solution of MSG, 1 does not show the sweetish and slightly soapy by-note, but evokes an intense umami taste. Aqueous solutions of 2 were described by the descriptors umami, seasoning, and bouillon-like. Added to a bouillon base, which did not contain any taste enhancers, both glycoconjugates imparted a distinct umami character similar to the control sample containing the same amount of MSG on a molar basis. To the best of our knowledge, these types of glycoconjugates in general and, in particular, N-glucosyl glutamate and N-deoxyfructosyl glutamate have never been reported as taste active compounds having umami-like properties. Therefore, 1 and 2 represent a new class of umami-type taste compounds showing properties similar to the umami reference compound MSG. Systematic (13)C NMR measurements revealed that 1 was fairly stable in aqueous solutions under alkaline conditions (pH 8-10) as well as in dry form. However, it rapidly hydrolyzes in neutral and acidic solutions, giving rise to glucose and glutamate. In contrast, glycoconjugate 2 was observed to be rather stable in aqueous solution as well as in the presence of human saliva.
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Affiliation(s)
- Ersan Beksan
- Deutsche Forschungsanstalt für Lebensmittelchemie, Lichtenbergstrasse 4, 85748 Garching, Germany
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17
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Grigorov MG, Schlichtherle-Cerny H, Affolter M, Kochhar S. Design of virtual libraries of umami-tasting molecules. JOURNAL OF CHEMICAL INFORMATION AND COMPUTER SCIENCES 2003; 43:1248-58. [PMID: 12870918 DOI: 10.1021/ci025652g] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The introduction of molecular tools in food research offers the possibility to the food industry to benefit from the experience gained in the field by pharmaceutical companies. In this work we are showing how in silico virtual screening techniques based on molecular similarity were applied for identifying novel umami-tasting compounds. The results obtained suggest that 5'-ribonucleotides and monosodium glutamate might elicit the fifth basic taste via the same molecular mechanism. New algorithms were developed and used in this work, such as the dimension reduction of data sets by singular value decomposition and the introduction of the correlation dimension as a natural dimension of a chemical space. It is shown that the representations of molecular data sets in chemical spaces possess self-similar properties, characteristic of fractal objects.
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Affiliation(s)
- Martin G Grigorov
- Nestlé Research Center, Vers-chez-les-Blanc, P.O. Box 44, CH-1000 Lausanne 26, Switzerland.
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18
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Mathiesen JM, Svendsen N, Bräuner-Osborne H, Thomsen C, Ramirez MT. Positive allosteric modulation of the human metabotropic glutamate receptor 4 (hmGluR4) by SIB-1893 and MPEP. Br J Pharmacol 2003; 138:1026-30. [PMID: 12684257 PMCID: PMC1573757 DOI: 10.1038/sj.bjp.0705159] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We have identified 2-methyl-6-(2-phenylethenyl)pyridine (SIB-1893) and 2-methyl-6-phenylethynyl pyridine hydrochloride (MPEP) as positive allosteric modulators for the hmGluR4. SIB-1893 and MPEP enhanced the potency and efficacy of L-2-amino-4-phophonobutyrate (L-AP4) in guanosine 5'-O-(3-[(35)S]thiotriphosphate ([(35)S]GTPgammaS) binding and efficacy in cAMP studies. These effects were fully blocked by the mGluR4 competitive antagonist (RS)-alpha-cyclopropyl-4-phosphonophenylglycine (CPPG), indicating a dependency on receptor activation. Although SIB-1893 and MPEP had no effects alone in GTPgammaS binding, effects were observed in the cell-based cAMP assay due to media-derived activation as indicated by CPPG inhibition. Positive modulation of the mGluR4 was a receptor-specific effect since SIB-1893 and MPEP had neither effects on mGluR2-expressing cells nor on the parent BHK cell line. In [(3)H]L-AP4 binding, a two-fold decrease in K(D) but not in B(max) was observed with 100 micro M SIB-1893, whereas MPEP affected neither parameter. Finally, SIB-1893 and MPEP failed to displace [(3)H]L-AP4 binding. Taken together, these data identify positive allosteric modulators for the hmGluR4.
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Affiliation(s)
- Jesper Mosolff Mathiesen
- Division of Biological Research, Department of Molecular Pharmacology, H. Lundbeck A/S, DK-2500 Valby, Denmark
- Department of Medicinal Chemistry, Danish University of Pharmaceutical Sciences DK-2100 Copenhagen, Denmark
| | - Nannette Svendsen
- Division of Biological Research, Department of Molecular Pharmacology, H. Lundbeck A/S, DK-2500 Valby, Denmark
| | - Hans Bräuner-Osborne
- Department of Medicinal Chemistry, Danish University of Pharmaceutical Sciences DK-2100 Copenhagen, Denmark
| | - Christian Thomsen
- Division of Biological Research, Department of Molecular Pharmacology, H. Lundbeck A/S, DK-2500 Valby, Denmark
| | - M Teresa Ramirez
- Division of Biological Research, Department of Molecular Pharmacology, H. Lundbeck A/S, DK-2500 Valby, Denmark
- Author for correspondence:
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Lorez M, Humbel U, Pflimlin MC, Kew JNC. Group III metabotropic glutamate receptors as autoreceptors in the cerebellar cortex. Br J Pharmacol 2003; 138:614-25. [PMID: 12598415 PMCID: PMC1573705 DOI: 10.1038/sj.bjp.0705099] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. Group III metabotropic glutamate receptors (mGluRs) of the subtype 4a are localized within presynaptic active zones of cerebellar parallel fibre (PF)-Purkinje cell (PC) synapses. In order to investigate the conditions necessary for group III mGluR autoreceptor-activation by synaptically released glutamate, we characterized the effects of selective agonists and antagonists on excitatory postsynaptic currents (EPSCs) evoked by several distinct PF stimulation patterns. 2. The group III mGluR-selective agonist L-AP4 depressed evoked EPSCs at PF-PC synapses in rat brain slices with an EC(50) of 2.4 microM and maximum inhibition of 80%. This L-AP4-induced depression was antagonized by the group III mGluR-selective antagonist MSOP with an estimated equilibrium dissaciation constant of 12.5 microM. 3. Paired-pulse or four-pulse PF stimulations did not activate presynaptic group III mGluRs as revealed by the lack of effect of 1 mM MSOP on relative test EPSC amplitudes with latencies of 250-500 ms. The potentiation of a test EPSC evoked 200-500 ms after a short tetanic burst (100 Hz for 60 ms), was also unchanged in the presence of MSOP. 4. Endogenous autoreceptor-activation was revealed only during prolonged stimulation trains (10 Hz for 4.4 s), where, in the presence of 1 mM MSOP, the EPSC amplitudes were enhanced by 15%. 5. These observations support an autoreceptor function of group III mGluRs and a role in short-term synaptic plasticity at PF synapses. However, the low to moderate activation levels observed, despite the close spatial relation with glutamate release sites, suggests that additional mechanisms regulate receptor activation.
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Affiliation(s)
- Matthias Lorez
- Pharma Division Pre-clinical Research, F Hoffmann-La Roche Ltd, CH-4002 Basel, Switzerland.
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Virus-based vectors for gene expression in mammalian cells: Semliki Forest virus. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0167-7306(03)38013-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Abstract
Semliki Forest virus (SFV), Sindbis virus (SIN), and Venezuelan equine encephalitis virus are simple, enveloped plus-strand RNA viruses belonging to the Alphavirus genus of the Togaviridae family. They have been developed into expression vectors that infect a wide host cell range and cause rapid and high-level transgene expression. Their easy and fast generation, classification into biosafety levels 1 and 2, and preferential transduction of neurons in cell and tissue cultures makes them an increasingly used gene transfer system. This review summarizes the alphaviral replication and expression, the replicon system, and its application in neurobiology. Alphaviral vectors can introduce multiple transgenes into host cells, and mutants with low or absent cytotoxicity and increased or decreased transgene expression levels are available. Temperature-dependent mutants permit to control the host cell specificity as well as the on- and offset of gene expression. These features, together with the transduction characteristics revealed in a direct comparison of alphaviral and other viral vectors in hippocampal slice cultures, make SFV and SIN vectors a powerful tool for neurobiological studies.
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Abstract
Alphaviruses are small, enveloped positive-strand RNA viruses that have been successfully transformed into expression vectors in the case of Semliki Forest virus (SFV), Sindbis virus (SIN), and Venezuelan equine encephalitis virus. Compared to other viral vectors, their advantages are easy and fast generation of recombinant viral particles, rapid onset, and high-level transgene expression. When applied to neuronal tissue, SFV and SIN vectors possess the additional advantage of efficiently and preferentially transducing neurons rather than non-neuronal cells. This article gives an overview of the biology of SFV and SIN, their generation into expression vectors, and their application in neurobiology, with particular emphasis on the transduction of hippocampal neurons. In addition, it describes the more recent development of alphaviral vectors with decreased or absent cytotoxicity and lowered transgene expression, temperature-controllable gene expression, and altered host-cell specificity in the central nervous system (CNS). Finally, the review evaluates the use of SFV and SIN vectors in hippocampal tissue cultures vs recombinant lentivirus, adenovirus type 5, adeno-associated virus type 2, and measles virus.
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Schlichtherle-Cerny H, Amadò R. Analysis of taste-active compounds in an enzymatic hydrolysate of deamidated wheat gluten. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2002; 50:1515-1522. [PMID: 11879030 DOI: 10.1021/jf010989o] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Hydrolyzed plant proteins are widely used as ingredients in culinary products for their glutamate-like ("umami") taste. Three hydrolysates were prepared from wheat gluten using different enzymatic approaches. Comparison of their taste profiles revealed the enzymatic hydrolysate of an acid-deamidated wheat gluten (WGH-3) to be the least bitter of all and to elicit an intense glutamate-like taste. Its umami taste intensity was similar to that of an enzymatic hydrolysate in which glutaminase had been employed to convert free glutamine to glutamic acid and which had a 3-fold higher concentration of free glutamate. Reconstitution studies based on the results of the chemical analysis of WGH-3 and sensory comparison of the model solution and WGH-3 indicated that other components in addition to glutamate and organic acids contribute to its glutamate-like taste. WGH-3 was fractionated by gel permeation chromatography and reversed phase high-performance liquid chromatography, and two fractions with a pronounced glutamate-like taste were obtained. In one of them four pyroglutamyl peptides were tentatively identified: pGlu-Pro-Ser, pGlu-Pro, pGlu-Pro-Glu, and pGlu-Pro-Gln. Apparently, these peptides were formed by cyclization of the N-terminal glutamine residues during the preparation of the hydrolysates.
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Affiliation(s)
- Hedwig Schlichtherle-Cerny
- Institute of Food Science, Swiss Federal Institute of Technology, ETH Zentrum, CH-8092 Zurich, Switzerland.
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Abstract
Since the discovery of its role in the CNS, glutamate, together with its involvement in signalling at synapses, has been the subject of a vast amount of research. More recently, it has become clear that glutamate signalling is also functional in non-neuronal tissues and occurs in sites as diverse as bone, pancreas and skin. These findings raise the possibility that glutamate acts as a more widespread 'cytokine' and is able to influence cellular activity in a range of tissue types. The impact of these discoveries is significant because they offer a rapid way to advance the development of therapeutics. Agents developed for use in neuroscience applications might be beneficial in the modulation of pathology peripherally, impacting on conditions such as osteoporosis, diabetes and wound healing.
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Affiliation(s)
- T M Skerry
- Dept of Biology, University of York, PO Box 373, YO10 5YW, UK.
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Abstract
Taste receptor cells use a variety of mechanisms to transduce chemical information into cellular signals. Seven-transmembrane-helix receptors initiate signaling cascades by coupling to G proteins, effector enzymes, second messengers and ion channels. Apical ion channels pass ions, leading to depolarizing and/or hyperpolarizing responses. New insights into the mechanisms of taste sensation have been gained from molecular cloning of the transduction elements, biochemical elucidation of the transduction pathways, and electrophysiological analysis of the function of taste cell ion channels.
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Affiliation(s)
- T A Gilbertson
- Department of Biology, Utah State University, Logan 84322-5305, USA.
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Chaudhari N, Landin AM, Roper SD. A metabotropic glutamate receptor variant functions as a taste receptor. Nat Neurosci 2000; 3:113-9. [PMID: 10649565 DOI: 10.1038/72053] [Citation(s) in RCA: 362] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Sensory transduction for many taste stimuli such as sugars, some bitter compounds and amino acids is thought to be mediated via G protein-coupled receptors (GPCRs), although no such receptors that respond to taste stimuli are yet identified. Monosodium L-glutamate (L-MSG), a natural component of many foods, is an important gustatory stimulus believed to signal dietary protein. We describe a GPCR cloned from rat taste buds and functionally expressed in CHO cells. The receptor couples negatively to a cAMP cascade and shows an unusual concentration-response relationship. The similarity of its properties to MSG taste suggests that this receptor is a taste receptor for glutamate.
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Affiliation(s)
- N Chaudhari
- Program in Neuroscience, University of Miami School of Medicine, P.O. Box 016430 (R430), Miami, Florida 33101, USA.
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