L-glutamate

• L-グルタミン酸、L-グルタミン酸塩

関

D-glutamate、glutamate、glutamic acid、L-glutamic acid

WordNet

1. the 12th letter of the Roman alphabet (同)l
2. a salt or ester of glutamic acid

PrepTutorEJDIC

1. lira(イタリアの貨幣単位リラ)
2. liter[s]

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2012/12/29 06:11:53」(JST)

wiki en

[Wiki en表示]

Glutamic acid
Systematic name 2-Aminopentanedioic acid
Other names Glutamic acid 2-Aminoglutaric acid
Identifiers
CAS number	617-65-2 Y
ChemSpider	591 Y
UNII	61LJO5I15S Y
KEGG	D04341 Y
ChEBI	CHEBI:18237 Y
ChEMBL	CHEMBL276389 Y
Jmol-3D images	Image 1
SMILES C(CC(=O)O)C(C(=O)O)N
InChI InChI=1S/C5H9NO4/c6-3(5(9)10)1-2-4(7)8/h3H,1-2,6H2,(H,7,8)(H,9,10) Y Key: WHUUTDBJXJRKMK-UHFFFAOYSA-N Y InChI=1/C5H9NO4/c6-3(5(9)10)1-2-4(7)8/h3H,1-2,6H2,(H,7,8)(H,9,10) Key: WHUUTDBJXJRKMK-UHFFFAOYAD
Properties
Molecular formula	C5H9NO4
Molar mass	147.13 g mol−1
Appearance	white crystalline powder
Density	1.4601 (20 °C)
Melting point	199 °C decomp.
Solubility in water	8.64 g/l (25 °C)
Solubility	0.00035g/100g ethanol 25 degC
Hazards
MSDS	External MSDS
NFPA 704	1 1 0
Supplementary data page
Structure and properties	n, εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Glutamic acid (abbreviated as Glu or E) is one of the 20-22 proteinogenic amino acids, and its codons are GAA and GAG. It is a non-essential amino acid. The carboxylate anions and salts of glutamic acid are known as glutamates. In neuroscience, glutamate is an important neurotransmitter that plays a key role in long-term potentiation and is important for learning and memory.

Chemistry

The side chain carboxylic acid functional group has a pK_a of 4.1 and exists in its negatively charged deprotonated carboxylate form at pHs greater than 4.1 therefore it is also negatively charged at physiological pH ranging from 7.35 to 7.45.

History

Main article: Glutamic acid (flavour)

Although they occur naturally in many foods, the flavour contributions made by glutamic acid and other amino acids were only scientifically identified early in the twentieth century. The substance was discovered and identified in the year 1866, by the German chemist Karl Heinrich Leopold Ritthausen who treated wheat gluten (for which it was named) with sulfuric acid. In 1907 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 flavour he detected in many foods, most especially in seaweed. Professor Ikeda termed this flavour umami. He then patented a method of mass-producing a crystalline salt of glutamic acid, monosodium glutamate.

Biosynthesis

Reactants	Products	Enzymes
Glutamine + H2O	→ Glu + NH3	GLS, GLS2
NAcGlu + H2O	→ Glu + Acetate	(unknown)
α-ketoglutarate + NADPH + NH4+	→ Glu + NADP+ + H2O	GLUD1, GLUD2
α-ketoglutarate + α-amino acid	→ Glu + α-keto acid	transaminase
1-Pyrroline-5-carboxylate + NAD+ + H2O	→ Glu + NADH	ALDH4A1
N-formimino-L-glutamate + FH4	→ Glu + 5-formimino-FH4	FTCD
NAAG	→ Glu + NAA	GCPII

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:

R₁-amino acid + R₂-α-ketoacid ⇌ R₁-α-ketoacid + R₂-amino acid

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:

Alanine + α-ketoglutarate ⇌ pyruvate + glutamate

Aspartate + α-ketoglutarate ⇌ oxaloacetate + glutamate

Both pyruvate and oxaloacetate are key components of cellular metabolism, contributing as substrates or intermediates in fundamental processes such as glycolysis, gluconeogenesis, and the citric acid cycle.

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, as follows:

glutamate + H₂O + NADP⁺ → α-ketoglutarate + NADPH + NH₃ + H⁺

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.

Neurotransmitter

Glutamate is the most abundant excitatory neurotransmitter in the vertebrate nervous system. At chemical synapses, glutamate is stored in vesicles. Nerve impulses trigger release of glutamate from the pre-synaptic cell. In the opposing post-synaptic cell, glutamate receptors, such as the NMDA receptor, bind glutamate and are activated. Because of its role in synaptic plasticity, glutamate is involved in cognitive functions like learning and memory in the brain. The form of plasticity known as long-term potentiation takes place at glutamatergic synapses in the hippocampus, neocortex, and other parts of the brain. Glutamate works not only as a point-to-point transmitter but also through spill-over synaptic crosstalk between synapses in which summation of glutamate released from a neighboring synapse creates extrasynaptic signaling/volume transmission.

Glutamate transporters are found in neuronal and glial membranes. They rapidly remove glutamate from the extracellular space. In brain injury or disease, they can work in reverse, and excess glutamate can accumulate outside cells. This process causes calcium ions to enter cells via NMDA receptor channels, leading to neuronal damage and eventual cell death, and is called excitotoxicity. The mechanisms of cell death include

• Damage to mitochondria from excessively high intracellular Ca²⁺

• Glu/Ca²⁺-mediated promotion of transcription factors for pro-apoptotic genes, or downregulation of transcription factors for anti-apoptotic genes

Excitotoxicity due to excessive glutamate release and impaired uptake occurs as part of the ischemic cascade and is associated with stroke and diseases like amyotrophic lateral sclerosis, lathyrism, autism, some forms of mental retardation, and Alzheimer's disease. In contrast, decreased glutamate release is observed under conditions of classical phenylketonuria leading to developmental disruption of glutamate receptor expression.

Glutamic acid has been implicated in epileptic seizures. Microinjection of glutamic acid into neurons produces spontaneous depolarisations around one second apart, and this firing pattern is similar to what is known as paroxysmal depolarizing shift in epileptic attacks. This change in the resting membrane potential at seizure foci could cause spontaneous opening of voltage-activated calcium channels, leading to glutamic acid release and further depolarization.

Experimental techniques to detect glutamate in intact cells include using a genetically-engineered nanosensor. The sensor is a fusion of a glutamate-binding protein and two fluorescent proteins. When glutamate binds, the fluorescence of the sensor under ultraviolet light changes by resonance between the two fluorophores. Introduction of the nanosensor into cells enables optical detection of the glutamate concentration. Synthetic analogs of glutamic acid that can be activated by ultraviolet light and two-photon excitation microscopy have also been described. This method of rapidly uncaging by photostimulation is useful for mapping the connections between neurons, and understanding synapse function.

Evolution of glutamate receptors is entirely the opposite in invertebrates, in particular, arthropods and nematodes, where glutamate stimulates glutamate-gated chloride channels.^{[citation needed]} The beta subunits of the receptor respond with very high affinity to glutamate and glycine. Targeting these receptors has been the therapeutic goal of anthelmintic therapy using avermectins. Avermectins target the alpha-subunit of glutamate-gated chloride channels with high affinity. These receptors have also been described in arthropods, such as Drosophila melanogaster and Lepeophtheirus salmonis. Irreversible activation of these receptors with avermectins results in hyperpolarization at synapses and neuromuscular junctions resulting in flaccid paralysis and death of nematodes and arthropods.

L-Glutamate at physiological conditions

Brain nonsynaptic glutamatergic signaling circuits

Extracellular glutamate in Drosophila brains has been found to regulate postsynaptic glutamate receptor clustering, via a process involving receptor desensitization. A gene expressed in glial cells actively transports glutamate into the extracellular space, while, in the nucleus accumbens-stimulating group II metabotropic glutamate receptors, this gene was found to reduce extracellular glutamate levels. This raises the possibility that this extracellular glutamate plays an "endocrine-like" role as part of a larger homeostatic system.

GABA precursor

Glutamate also serves as the precursor for the synthesis of the inhibitory GABA in GABA-ergic neurons. This reaction is catalyzed by glutamate decarboxylase (GAD), which is most abundant in the cerebellum and pancreas.

Stiff-man 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 is also abundant for the enzyme GAD, a direct immunological destruction occurs in the pancreas and the patients will have diabetes mellitus.

Flavor enhancer

Main article: Glutamic acid (flavor)

Glutamic acid, being a constituent of protein, is present in every food that contains 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 cheese and soy sauce, and is responsible for umami, one of the five basic tastes of the human sense of taste. Glutamic acid is often used as a food additive and flavour enhancer in the form of its 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. Thirty to 35% of the protein in wheat is glutamic acid. Ninety-five percent of the dietary glutamate is metabolized by intestinal cells in a first pass.

Plant growth

Auxigro is a plant growth preparation that contains 30% glutamic acid.

NMR spectroscopy

In recent years, there has been much research into the use of RDCs in NMR spectroscopy. A glutamic acid derivative, poly-γ-benzyl-L-glutamate (PBLG), is often used as an alignment medium to control the scale of the dipolar interactions observed.

Production

China-based Fufeng Group Limited is the largest producer of glutamic acid in the world, with capacity increasing to 300,000 tons at the end of 2006 from 180,000 tons during 2006, putting them at 25%–30% of the Chinese market. Meihua is the second-largest Chinese producer. Together, the top-five producers have roughly 50% share in China. Chinese demand is roughly 1.1 million tons per year, while global demand, including China, is 1.7 million tons per year.

Pharmacology

The drug phencyclidine (more commonly known as PCP) antagonizes glutamic acid non-competitively at the NMDA receptor. For the same reasons, dextromethorphan and ketamine also have strong dissociative and hallucinogenic effects. Glutamate does not easily pass the blood brain barrier, but, instead, is transported by a high-affinity transport system. It can also be converted into glutamine.

See also

• Kainic acid
• Disodium glutamate
• Monosodium glutamate

References

Further reading

• Nelson, David L.; Cox, Michael M. (2005), Principles of Biochemistry (4th ed.), New York: W. H. Freeman, ISBN 0-7167-4339-6

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English Journal

• Glutamic acid promotes monacolin K production and monacolin K biosynthetic gene cluster expression in Monascus.

• Zhang C1,2,3, Liang J1,2, Yang L1,3, Chai S1,3, Zhang C1,3, Sun B1,2,3, Wang C4,5,6,7.
• AMB Express.AMB Express.2017 Dec;7(1):22. doi: 10.1186/s13568-016-0311-z. Epub 2017 Jan 10.
• This study investigated the effects of glutamic acid on production of monacolin K and expression of the monacolin K biosynthetic gene cluster. When Monascus M1 was grown in glutamic medium instead of in the original medium, monacolin K production increased from 48.4 to 215.4 mg l-1, monacolin K pr
• PMID 28070827

• Formulation of yeast-leavened bread with reduced salt content by using a Lactobacillus plantarum fermentation product.

• Valerio F1, Conte A2, Di Biase M1, Lattanzio VM1, Lonigro SL1, Padalino L3, Pontonio E4, Lavermicocca P5.
• Food chemistry.Food Chem.2017 Apr 15;221:582-589. doi: 10.1016/j.foodchem.2016.11.135. Epub 2016 Nov 25.
• A Lactobacillus plantarum fermentation product (Bio21B), obtained after strain growth (14h) in a wheat flour-based medium, was applied in the bread-making process as taste enhancer, in order to obtain a yeast-leavened bread with reduced salt content (20% and 50%) with respect to a reference bread (R
• PMID 27979245

• Kinetics of browning and correlations between browning degree and pyrazine compounds in l-ascorbic acid/acidic amino acid model systems.

• Yu AN1, Zhou YY2, Yang YN2.
• Food chemistry.Food Chem.2017 Apr 15;221:1678-1684. doi: 10.1016/j.foodchem.2016.10.119. Epub 2016 Oct 27.
• The kinetics of browning and the correlation between browning products (BPs) and pyrazine compounds were investigated by heating equimolar l-ascorbic acid (ASA)/acidic amino acids under weak alkaline conditions at 120-150°C for 10-120min. The formations of BPs and pyrazine compounds from the reacti
• PMID 27979146

Japanese Journal

• エクストリモライトとしてのポリ-γ-L-グルタミン酸とその応用 (特集 新機能素材の創製と実用化)

• 芦内 誠
• 化学工業 63(5), 390-396, 2012-05
• NAID 40019308385

• Preparation of poly(γ-benzyl-L-glutamate) nanofibers by electrospinning from isotropic and biphasic liquid crystal solutions

• TSUBOI Kazuma,MARCELLETTI Erika,MATSUMOTO Hidetoshi,ASHIZAWA Minoru,MINAGAWA Mie,FURUYA Hidemine,TANIOKA Akihiko,ABE Akihiro
• Polymer journal 44(4), 360-365, 2012-04-15
• NAID 10030516437

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★リンクテーブル★

リンク元	「グルタミン酸」「L-glutamic acid」「L-グルタミン酸」「D-glutamate」「L-グルタミン酸塩」
拡張検索	「monosodium L-glutamate monohydrate」「monosodium L-glutamate」
関連記事	「glutamate」「L」

「グルタミン酸」

　　[★]

英

glutamate, glutamic acid, Glu, E

同

α-アミノグルタル酸 2-アミノグルタル酸 2-アミノペンタン二酸 2-aminopentanedioic acid

関

アミノ酸、D-glutamate、L-glutamate

概念

• 極性。酸性。
• 生理活性アミン。4-アミノ酪酸、GABAの材料
• カルボキシル基を有する。
• アラニンの側鎖に-CH2-がつき、さらにカルボキシル基がついた形をしている。

-CH2-CH2-COOH

「L-glutamic acid」

　　[★]

L-グルタミン酸

関

D-glutamate、E、Glu、glutamate、glutamic、glutamic acid、L-glutamate

「L-グルタミン酸」

　　[★]

英

L-glutamic acid、L-glutamate

関

グルタミン酸、L-グルタミン酸塩、D-グルタミン酸

「D-glutamate」

　　[★]

D-グルタミン酸

関

glutamate、glutamic acid、L-glutamate、L-glutamic acid

「L-グルタミン酸塩」

　　[★]

英

L-glutamate

関

グルタミン酸、L-グルタミン酸、D-グルタミン酸

「monosodium L-glutamate monohydrate」

　　[★]

• L-グルタミン酸一ナトリウム一水和物、L-グルタミン酸ナトリウム、グルタミン酸ナトリウム

関

monosodium glutamate、monosodium L-glutamate、MSG、sodium glutamate

「monosodium L-glutamate」

　　[★]

• L-グルタミン酸ナトリウム

関

monosodium glutamate、monosodium L-glutamate monohydrate、MSG、sodium glutamate

「glutamate」

　　[★]

グルタミン酸、グルタメート、グルタメイト、(化合物)グルタミン酸塩

　

「L」

　　[★]

• リシジン
• リンキング数
• ロイシン
• free ligand concentration