Glutamic acid (symbol Glu or E;[4] the anionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can synthesize enough for its use. It is also the most abundant excitatory neurotransmitter in the vertebrate nervous system. It serves as the precursor for the synthesis of the inhibitory gamma-aminobutyric acid (GABA) in GABAergic neurons.
Its molecular formula is C 5H 9NO 4. Glutamic acid exists in two optically isomeric forms; the dextrorotatoryL-form is usually obtained by hydrolysis of gluten or from the waste waters of beet-sugar manufacture or by fermentation.[5][full citation needed] Its molecular structure could be idealized as HOOC−CH(NH 2)−(CH 2)2−COOH, with two carboxyl groups −COOH and one amino group −NH 2. However, in the solid state and mildly acidic water solutions, the molecule assumes an electrically neutralzwitterion structure −OOC−CH(NH+ 3)−(CH 2)2−COOH. It is encoded by the codons GAA or GAG.
The acid can lose one proton from its second carboxyl group to form the conjugate base, the singly-negative anionglutamate−OOC−CH(NH+ 3)−(CH 2)2−COO−. This form of the compound is prevalent in neutral solutions. The glutamate neurotransmitter plays the principal role in neural activation.[6] This anion creates the savory umami flavor of foods and is found in glutamate flavorings such as MSG. In Europe, it is classified as food additive E620. In highly alkaline solutions the doubly negative anion −OOC−CH(NH 2)−(CH 2)2−COO− prevails. The radical corresponding to glutamate is called glutamyl.
The one-letter symbol E for glutamate was assigned as the letter following D for aspartate, as glutamate is larger by one methylene –CH2– group.[7]
Chemistry
Ionization
When glutamic acid is dissolved in water, the amino group (−NH 2) may gain a proton (H+ ), and/or the carboxyl groups may lose protons, depending on the acidity of the medium.
In sufficiently acidic environments, both carboxyl groups are protonated and the molecule becomes a cation with a single positive charge, HOOC−CH(NH+ 3)−(CH 2)2−COOH.[8]
At pH values between about 2.5 and 4.1,[8] the carboxylic acid closer to the amine generally loses a proton, and the acid becomes the neutral zwitterion−OOC−CH(NH+ 3)−(CH 2)2−COOH. This is also the form of the compound in the crystalline solid state.[9][10] The change in protonation state is gradual; the two forms are in equal concentrations at pH 2.10.[11]
At even higher pH, the other carboxylic acid group loses its proton and the acid exists almost entirely as the glutamate anion−OOC−CH(NH+ 3)−(CH 2)2−COO−, with a single negative charge overall. The change in protonation state occurs at pH 4.07.[11] This form with both carboxylates lacking protons is dominant in the physiological pH range (7.35–7.45).
At even higher pH, the amino group loses the extra proton, and the prevalent species is the doubly-negative anion −OOC−CH(NH 2)−(CH 2)2−COO−. The change in protonation state occurs at pH 9.47.[11]
Although they occur naturally in many foods, the flavor contributions made by glutamic acid and other amino acids were only scientifically identified early in the 20th century. The substance was discovered and identified in the year 1866 by the German chemist Karl Heinrich Ritthausen, who treated wheat gluten (for which it was named) with sulfuric acid.[14] In 1908, Japanese researcher Kikunae Ikeda of the Tokyo Imperial University identified brown crystals left behind after the evaporation of a large amount of kombu broth as glutamic acid. These crystals, when tasted, reproduced the ineffable but undeniable flavor he detected in many foods, most especially in seaweed. Professor Ikeda termed this flavor umami. He then patented a method of mass-producing a crystalline salt of glutamic acid, monosodium glutamate.[15][16]
Glutamic acid is produced on the largest scale of any amino acid, with an estimated annual production of about 1.5 million tons in 2006.[18] Chemical synthesis was supplanted by the aerobic fermentation of sugars and ammonia in the 1950s, with the organism Corynebacterium glutamicum (also known as Brevibacterium flavum) being the most widely used for production.[19] Isolation and purification can be achieved by concentration and crystallization; it is also widely available as its hydrochloride salt.[20]
Function and uses
Metabolism
Glutamate is a key compound in cellular metabolism. In humans, dietary proteins are broken down by digestion into amino acids, which serve as metabolic fuel for other functional roles in the body. A key process in amino acid degradation is transamination, in which the amino group of an amino acid is transferred to an α-ketoacid, typically catalysed by a transaminase. The reaction can be generalised as such:
A very common α-keto acid is α-ketoglutarate, an intermediate in the citric acid cycle. Transamination of α-ketoglutarate gives glutamate. The resulting α-ketoacid product is often a useful one as well, which can contribute as fuel or as a substrate for further metabolism processes. Examples are as follows:
Glutamate also plays an important role in the body's disposal of excess or waste nitrogen. Glutamate undergoes deamination, an oxidative reaction catalysed by glutamate dehydrogenase,[17] as follows:
Ammonia (as ammonium) is then excreted predominantly as urea, synthesised in the liver. Transamination can thus be linked to deamination, effectively allowing nitrogen from the amine groups of amino acids to be removed, via glutamate as an intermediate, and finally excreted from the body in the form of urea.
Glutamate is also a neurotransmitter (see below), which makes it one of the most abundant molecules in the brain. Malignant brain tumors known as glioma or glioblastoma exploit this phenomenon by using glutamate as an energy source, especially when these tumors become more dependent on glutamate due to mutations in the gene IDH1.[21][22]
Extracellular glutamate in Drosophila brains has been found to regulate postsynaptic glutamate receptor clustering, via a process involving receptor desensitization.[26] A gene expressed in glial cells actively transports glutamate into the extracellular space,[26] while, in the nucleus accumbens-stimulating group II metabotropic glutamate receptors, this gene was found to reduce extracellular glutamate levels.[27] This raises the possibility that this extracellular glutamate plays an "endocrine-like" role as part of a larger homeostatic system.
Stiff person syndrome is a neurologic disorder caused by anti-GAD antibodies, leading to a decrease in GABA synthesis and, therefore, impaired motor function such as muscle stiffness and spasm. Since the pancreas has abundant GAD, a direct immunological destruction occurs in the pancreas and the patients will have diabetes mellitus.[31]
Glutamic acid, being a constituent of protein, is present in foods that contain protein, but it can only be tasted when it is present in an unbound form. Significant amounts of free glutamic acid are present in a wide variety of foods, including cheeses and soy sauce, and glutamic acid is responsible for umami, one of the five basic tastes of the human sense of taste. Glutamic acid often is used as a food additive and flavor enhancer in the form of its sodium salt, known as monosodium glutamate (MSG).
Nutrient
All meats, poultry, fish, eggs, dairy products, and kombu are excellent sources of glutamic acid. Some protein-rich plant foods also serve as sources. 30% to 35% of gluten (much of the protein in wheat) is glutamic acid. Ninety-five percent of the dietary glutamate is metabolized by intestinal cells in a first pass.[32]
Plant growth
Auxigro is a plant growth preparation that contains 30% glutamic acid.
^Webster's Third New International Dictionary of the English Language Unabridged, Third Edition, 1971.
^Robert Sapolsky (2005), Biology and Human Behavior: The Neurological Origins of Individuality (2nd edition); The Teaching Company. pp. 19–20 of the Guide Book.
^ abAlbert Neuberger (1936), "Dissociation constants and structures of glutamic acid and its esters". Biochemical Journal, volume 30, issue 11, article CCXCIII, pp. 2085–2094. PMC1263308.
^Rodante, F.; Marrosu, G. (1989). "Thermodynamics of the second proton dissociation processes of nine α-amino-acids and the third ionization processes of glutamic acid, aspartic acid and tyrosine". Thermochimica Acta. 141: 297–303. Bibcode:1989TcAc..141..297R. doi:10.1016/0040-6031(89)87065-0.
^Lehmann, Mogens S.; Koetzle, Thomas F.; Hamilton, Walter C. (1972). "Precision neutron diffraction structure determination of protein and nucleic acid components. VIII: the crystal and molecular structure of the β-form of the amino acidl-glutamic acid". Journal of Crystal and Molecular Structure. 2 (5): 225–233. Bibcode:1972JCCry...2..225L. doi:10.1007/BF01246639. S2CID93590487.
^ abcWilliam H. Brown and Lawrence S. Brown (2008), Organic Chemistry (5th edition). Cengage Learning. p. 1041. ISBN0495388572, 978-0495388579.
^National Center for Biotechnology Information, "D-glutamate". PubChem Compound Database, CID=23327. Accessed 2017-02-17.
^R. H. A. Plimmer (1912) [1908]. R. H. A. Plimmer; F. G. Hopkins (eds.). The Chemical Constitution of the Protein. Monographs on biochemistry. Vol. Part I. Analysis (2nd ed.). London: Longmans, Green and Co. p. 114. Retrieved 3 June 2012.
^McEntee, W. J.; Crook, T. H. (1993). "Glutamate: Its role in learning, memory, and the aging brain". Psychopharmacology. 111 (4): 391–401. doi:10.1007/BF02253527. PMID7870979. S2CID37400348.
^C. M. Thiele, Concepts Magn. Reson. A, 2007, 30A, 65–80
^Coplan JD, Mathew SJ, Smith EL, Trost RC, Scharf BA, Martinez J, Gorman JM, Monn JA, Schoepp DD, Rosenblum LA (July 2001). "Effects of LY354740, a novel glutamatergic metabotropic agonist, on nonhuman primate hypothalamic-pituitary-adrenal axis and noradrenergic function". CNS Spectr. 6 (7): 607–612, 617. doi:10.1017/S1092852900002157. PMID15573025. S2CID6029856.
^Felizola SJ, Nakamura Y, Satoh F, Morimoto R, Kikuchi K, Nakamura T, Hozawa A, Wang L, Onodera Y, Ise K, McNamara KM, Midorikawa S, Suzuki S, Sasano H (January 2014). "Glutamate receptors and the regulation of steroidogenesis in the human adrenal gland: The metabotropic pathway". Molecular and Cellular Endocrinology. 382 (1): 170–177. doi:10.1016/j.mce.2013.09.025. PMID24080311. S2CID3357749.
Ugyen WangchuckRaja Bhutan PertamaBerkuasa17 Desember 1907–21 Agustus 1926PendahuluTidak adaPenerusJigme WangchuckWangsaWangchuck DynastyAyahJigme NamgyalIbuAshi Pema ChokiAnakJigme Wangchuck Lemo Wangchuck Lhadron Wangchuck Gongsa Ugyen Wangchuck (Dzongkha: , Wylie: o rgyan dbang phyug; 1862-1926) adalah Raja Bhutan pertama yang berkuasa dari tahun 1907 hingga 1926. Ia lahir pada tahun 1862 sebagai putra dari pasangan Jigme Namgyal, seorang penlop (gubernur) Trongsa, dan Ashi Pema Choki. I...
Indian Urdu language poet, author, critic, and theorist (1935–2020) This article is about the Indian Urdu poet. For the Bangladeshi Bengali poet, see Shamsur Rahman (poet). Shamsur Rahman FaruqiBornShamsur Rahman Faruqi30 September 1935Pratapgarh, United Provinces, British India (now in Uttar Pradesh, India)Died25 December 2020(2020-12-25) (aged 85)Allahabad, Uttar Pradesh, IndiaResting placeAshok Nagar, Allahabad, beside his wifeOccupationPoet, criticLanguageUrduNationalityIndianAlma&...
1978 science fiction novel by Jan Mark First edition (UK) The Ennead is a novel by Jan Mark published in 1978 by Viking Kestrel in the UK and Thomas Y. Crowell in the US. Plot summary The Ennead is a novel set on the planet Erato, whose provincial inhabitants seek to control overpopulation by limiting the population and restricting immigration from the nearby planet Euterpe.[1] Reception Kirkus Reviews states though the playing out of her theme follows a standard outline, Mark's chara...
Former exhibition building in New York City New York Crystal PalaceNew York Crystal Palace designed by Karl Gildemeister and Georg Carstensen. The image is an oil-color plate by George Baxter, London, dated September 1, 1853General informationStatusDestroyedTypeExhibition palaceTown or cityNew York CityCountryUnited States of AmericaCoordinates40°45′13″N 73°59′02″W / 40.75361°N 73.98389°W / 40.75361; -73.98389InauguratedJuly 14, 1853DestroyedOctober 5, 1858...
الوطنية للمقاولات العامة والتوريداتالوطنية للمقاولات العامة والتوريداتالشعارمعلومات عامةالبلد مصرالتأسيس 1995 (منذ 29 سنة)المقر الرئيسي القاهرة، مصرالمنظومة الاقتصاديةالشركة الأم جهاز مشروعات الخدمة الوطنية للقوات المسلحةالنشاط التشييد والبناءمناطق الخدمة جمهو...
Sonny Widjaja Komandan Sekolah Staf dan Komando TNI ke-35Masa jabatan15 Agustus 2014 – 1 Februari 2016 PendahuluIsmono WijayantoPenggantiAgus SutomoPanglima Kodam III/SiliwangiMasa jabatan20 Februari 2012 – 18 Agustus 2013 PendahuluMuhammad MunirPenggantiDedi Kusnadi Thamim Informasi pribadiLahir1 Januari 1958 (umur 66)Klaten, Jawa TengahKebangsaanIndonesiaAlma materAkademi Militer (1982)Karier militerPihak IndonesiaDinas/cabang TNI Angkatan DaratMasa ...
Artikel ini bukan mengenai Kebijakan. Kebajikan-Kebajikan Asasi dan Teologis karya Rafael, 1511 Kebajikan adalah kemuliaan akhlak. Suatu kebajikan adalah tabiat atau sifat tertentu yang dianggap baik, sehingga dijadikan salah satu sendi keutamaan dan sikap berbudi pekerti yang baik. Dengan kata lain, kebajikan adalah perilaku yang memperlihatkan tolok ukur budi pekerti yang tinggi, yakni mengerjakan yang benar dan menghindari yang salah. Lawan dari kebajikan adalah kefasikan. Contoh-contoh la...
American politician Solon BorlandEnvoy Extraordinary and Minister Plenipotentiary (Nicaragua)In officeApril 18, 1853 – April 17, 1854PresidentFranklin PiercePreceded byJohn B. KerrSucceeded byJohn H. WheelerUnited States Senatorfrom ArkansasIn officeApril 24, 1848 – March 3, 1853Preceded byAmbrose Hundley SevierSucceeded byRobert Ward Johnson Personal detailsBorn(1808-09-21)September 21, 1808Nansemond County, Virginia, U.S.DiedJanuary 1, 1864(1864-01-01) (aged 55)Ha...
Cet article est une ébauche concernant un conflit armé. Vous pouvez partager vos connaissances en l’améliorant (comment ?) selon les recommandations des projets correspondants. Bataille du lac Champlain ou Bataille de Plattsburgh Informations générales Date du 6 au 11 septembre 1814 Lieu Plattsburgh dans l'État de New York Issue Victoire importante des États-Unis Belligérants Royaume-Uni États-Unis Commandants George Prévost, George Downie (en) Thomas Macdonough, Alexan...
Questa voce sull'argomento Stagioni delle società calcistiche italiane è solo un abbozzo. Contribuisci a migliorarla secondo le convenzioni di Wikipedia. Segui i suggerimenti del progetto di riferimento. Voce principale: Unione Sportiva Milanese. Unione Sportiva MilaneseStagione 1925-1926Sport calcio Squadra US Milanese Allenatore Commissione Esecutiva rag. Giuseppe Binaghi, Beniamino Cairoli, Agostino Recalcati, Piero Poini, Achille Colombo, Arturo Leidi, ten. Giacinto Tosca, Vi...
The HonourableDean Oliver Barrow Perdana Menteri Belize ke-4Masa jabatan8 Februari 2008 – 12 November 2020Penguasa monarkiElizabeth IIGubernur JenderalColville YoungWakilGaspar VegaPendahuluSaid MusaPenggantiJohnny BriceñoDaerah pemilihanQueen's Square Informasi pribadiLahir2 Maret 1951 (umur 73)Partai politikPartai Demokrat BersatuSuami/istriKim Simpliss (pernikahan ke-2)ProfesiPengacaraSunting kotak info • L • B Dean Oliver Barrow (lahir 2 Maret 1951) adalah s...
District of West Bengal, India District in West Bengal, IndiaDarjeeling districtDistrict Clockwise from top-left: Tea estate in Darjeeling, Darjeeling Himalayan Railway, Ghum Monastery, View of Kangchenjunga from Tiger Hill, View of SiliguriLocation of Darjeeling in West BengalCountry IndiaState West BengalDivisionJalpaiguriHeadquartersDarjeelingGovernment • Lok Sabha constituenciesDarjeeling (shared with Kalimpong district) • Vidhan Sabha constituenciesDarjeeling...
Trattato di AquisgranaLondra, fuochi d'artificio per celebrare la gioia inglese per la fine della guerra di successione austriaca.Tipotrattato di pace ContestoGuerra di successione austriaca Firma18 ottobre 1748 LuogoAquisgrana PartiImpero britannicoPaesi BassiRegno di FranciaAustriaImpero spagnoloRegno di SardegnaRepubblica di Genova e Ducato di Modena e Reggio Firmatari Arciducato d'Austria Gran Bretagna Province Unitee alleati (Lega Prammatica) Regno di Prussia Regno di Francia Regno di Na...
German research institution Institute for Media and Communication PolicyInstitut für Medien- und KommunikationspolitikLocationCologne, GermanyWebsitewww.medienpolitik.eu The Institute for Media and Communication Policy (IfM) was founded in 2005 as an independent research institution that is exclusively dedicated to issues surrounding media and communication policies. It was established in February 2006 in Berlin-Charlottenburg, but in November 2014 it moved to Cologne. The institute is funde...
American film production and distribution company This article is about the former mini-major, now CBS Entertainment Group film studio production company. For the former television syndication firm, CBS Films Inc., see Viacom (1952–2006). CBS Films Inc.Company typeSubsidiary[1]IndustryFilmPredecessorCBS Theatrical FilmsFoundedMarch 2007; 17 years ago (March 2007)[2]FounderLeslie Moonves[1]DefunctDecember 4, 2019; 4 years ago (December 4, 201...
Luwu Timur pada Pekan Olahraga Provinsi Sulawesi Selatan 2022 Jumlah atlet 220 di 22 cabang olahraga Pembawa bendera TBD Total medali Emas9 Perak13 Perunggu25 47 (Urutan ke-15 ) Kontingen Luwu Timur berkompetisi pada Pekan Olahraga Provinsi Sulawesi Selatan 2022 di Sinjai dan Bulukumba, Sulawesi Selatan pada 22 sampai 30 Oktober 2022. Kontingen ini menempati posisi ke-15 pada tabel klasemen perolehan medali Porprov Sulsel XVII/2022 setelah meraih total medali 47 dengan rincian 9 medali ...
نورمان رامسي (بالإنجليزية: Norman Foster Ramsey, Jr.) معلومات شخصية الميلاد 27 أغسطس 1915 [1][2][3][4] واشنطن العاصمة[5][6][7] الوفاة 4 نوفمبر 2011 (96 سنة) [8][9][10][1][2][3] مقاطعة ميدلسيكس الإقامة بوسطن مواطنة الولايات المت�...
بريندا غونزاليس معلومات شخصية الميلاد سنة 1993 (العمر 30–31 سنة) روساريو مواطنة الأرجنتين الحياة العملية المهنة متسابقة ملكة الجمال تعديل مصدري - تعديل بريندا غونزاليس (بالإسبانية: Brenda González) هي متسابقة ملكة الجمال أرجنتينية، ولدت في 1993 في روساريو في الأر�...
From left to right: Ted, Robin, Barney, Marshall, Lily. The US sitcom How I Met Your Mother premiered on CBS on September 19, 2005. Created by Craig Thomas and Carter Bays, the show is presented from the perspective of Ted Mosby in 2030 (Future Ted) as he tells his children how he met the titular mother. The show lasted for nine seasons and 208 episodes; the finale first aired on March 31, 2014. A stand-alone sequel series, How I Met Your Father, premiered on Hulu on January 18, 2022. Create...
2020 single by Jazmine Sullivan Lost OneSingle by Jazmine Sullivanfrom the EP Heaux Tales ReleasedAugust 28, 2020 (2020-08-28)Length3:00LabelRCASongwriter(s) Jazmine Sullivan Dave Watson Producer(s)Dave WatsonJazmine Sullivan singles chronology Hard to Believe (2019) Lost One (2020) Pick Up Your Feelings (2020) Lost One is a song recorded by American singer-songwriter Jazmine Sullivan. It was released by RCA Records on August 28, 2020, as the lead single from her debut exte...