![]() Skeletal formula of L-aspartic acid
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IUPAC name
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Other names
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Identifiers | |||
3D model (JSmol)
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ChEBI |
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ChEMBL |
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ChemSpider | |||
DrugBank |
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ECHA InfoCard | 100.000.265 | ||
EC Number |
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KEGG |
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PubChem CID
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UNII |
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CompTox Dashboard (EPA)
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Properties | |||
C4H7NO4 | |||
Molar mass | 133.103 g·mol−1 | ||
Appearance | colourless crystals | ||
Density | 1.7 g/cm3 | ||
Melting point | 270 °C (518 °F; 543 K) | ||
Boiling point | 324 °C (615 °F; 597 K) (decomposes) | ||
4.5 g/L[2] | |||
Acidity (pKa) |
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Conjugate base | Aspartate | ||
-64.2·10−6 cm3/mol | |||
Hazards | |||
NFPA 704 (fire diamond) | |||
Supplementary data page | |||
Aspartic acid (data page) | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Aspartic acid (symbol Asp or D;[4] the ionic form is known as aspartate), is an α-amino acid that is used in the biosynthesis of proteins.[5] The L-isomer of aspartic acid is one of the 22 proteinogenic amino acids, i.e., the building blocks of proteins. D-aspartic acid is one of two D-amino acids commonly found in mammals.[6][7] Apart from a few rare exceptions, D-aspartic acid is not used for protein synthesis but is incorporated into some peptides and plays a role as a neurotransmitter/neuromodulator.[6]
Like all other amino acids, aspartic acid contains an amino group and a carboxylic acid. Its α-amino group is in the protonated –NH+
3 form under physiological conditions, while its α-carboxylic acid group is deprotonated −COO− under physiological conditions. Aspartic acid has an acidic side chain (CH2COOH) which reacts with other amino acids, enzymes and proteins in the body.[5] Under physiological conditions (pH 7.4) in proteins the side chain usually occurs as the negatively charged aspartate form, −COO−.[5] It is a non-essential amino acid in humans, meaning the body can synthesize it as needed. It is encoded by the codons GAU and GAC.
In proteins aspartate sidechains are often hydrogen bonded to form asx turns or asx motifs, which frequently occur at the N-termini of alpha helices.
Aspartic acid, like glutamic acid, is classified as an acidic amino acid, with a pKa of 3.9; however, in a peptide this is highly dependent on the local environment, and could be as high as 14.
The one-letter code D for aspartate was assigned arbitrarily,[8] with the proposed mnemonic asparDic acid.[9]
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