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Topic summary

Glutamic acid

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Names IUPAC name
Glutamic acid
Systematic IUPAC name
2-Aminopentanedioic acid
Other names
  • 2-Aminoglutaric acid
Identifiers
3D model (JSmol)
1723801 (L) 1723799 (rac) 1723800 (D) ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard100.009.567EC Number
  • l isomer: 200-293-7
E numberE620 (flavour enhancer)3502 (L) 101971 (rac) 201189 (D) KEGG
UNII
  • InChI=1S/C5H9NO4/c6-3(5(9)10)1-2-4(7)8/h3H,1-2,6H2,(H,7,8)(H,9,10)
    Key: WHUUTDBJXJRKMK-UHFFFAOYSA-N
  • l isomer: 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
  • l isomer: C(CC(=O)O)[C@@H](C(=O)O)N
  • d isomer: C(CC(=O)O)[C@H](C(=O)O)N
  • Zwitterion: C(CC(=O)O)C(C(=O)[O-])[NH3+]
  • Deprotonated zwitterion: C(CC(=O)[O-])C(C(=O)[O-])[NH3+]
Properties C5H9NO4Molar mass147.130 g·mol Appearance White crystalline powder Density1.4601 (20 Â°C) Melting point199 Â°C (390 Â°F; 472 K) decomposes 8.57 g/L (25 Â°C) SolubilityEthanol: 350 Î¼g/100 g (25 Â°C) Acidity (pKa)
  • 2.10 (α-carboxyl; H2O)
  • 4.07 (side chain; H2O)
  • 9.47 (α-amino; H2O)
−78.5·10 cm/mol Hazards GHS labelling: WarningH315, H319, H335P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501NFPA 704 (fire diamond)
2
1
0
Supplementary data page Glutamic acid (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 Â°C [77 Â°F], 100 kPa).

Glutamic acid (symbol Glu or E; known as glutamate in its anionic form), molecular formulaC
5H
9NO
4, is an α-amino acid that is used by almost all organisms for the biosynthesis of proteins. It is an conditionally essential amino acid, meaning that the body can generally synthesize it intrinsically, but under certain circumstances needs to procure it through food. It is also the most abundant excitatory neurotransmitter in the vertebratenervous system. It serves as the precursor for the synthesis of the inhibitory gamma-aminobutyric acid (GABA) in GABAergicneurons.

Glutamic acid exists in two optically isomeric forms; the dextrorotaryL-form is usually obtained by hydrolysis of gluten, from the waste waters of beet-sugar manufacturing, or by fermentation. 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 anion glutamate 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. This anion creates the savory umami flavor of foods and is found in glutamate flavorings such as monosodium glutamate (MSG). In Europe, it is classified as food additive E621 [for monosodium glutamate] and E620 [for glutamic acid itself]. 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.

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