Aspartic acid
IUPAC name Trivial: Aspartic acid Systematic: 2-Aminobutanedioic acid
Other names Aminosuccinic acid, asparagic acid, asparaginic acid[1]
Identifiers
CAS number	617-45-8 Y,  56-84-8 (L-isomer) 1783-96-6 (D-isomer)
PubChem	424
ChemSpider	411 Y
UNII	28XF4669EP Y
EC-number	200-291-6
KEGG	C16433 Y
ChEBI	CHEBI:22660 Y
ChEMBL	CHEMBL139661 Y
Jmol-3D images	Image 1 Image 2
SMILES O=C(O)CC(N)C(=O)O C(C(C(=O)O)N)C(=O)O
InChI InChI=1S/C4H7NO4/c5-2(4(8)9)1-3(6)7/h2H,1,5H2,(H,6,7)(H,8,9) Y Key: CKLJMWTZIZZHCS-UHFFFAOYSA-N Y InChI=1/C4H7NO4/c5-2(4(8)9)1-3(6)7/h2H,1,5H2,(H,6,7)(H,8,9) Key: CKLJMWTZIZZHCS-UHFFFAOYAE
Properties
Molecular formula	C4H7NO4
Molar mass	133.10 g mol−1
Appearance	colourless crystals
Density	1.7 g/cm3
Melting point	270°C
Boiling point	324°C (decomposes)
Solubility in water	4.5 g/L [2]
Acidity (pKa)	3.9
Hazards
MSDS	External MSDS
EU Index	not listed
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

Aspartic acid (abbreviated as Asp or D)^[3] is an α-amino acid with the chemical formula HOOCCH(NH₂)CH₂COOH. The carboxylate anion, salt, or ester of aspartic acid is known as aspartate. The L-isomer of aspartate is one of the 20 proteinogenic amino acids, i.e., the building blocks of proteins. Its codons are GAU and GAC.

Aspartic acid is, together with glutamic acid, classified as an acidic amino acid with a pK_a of 3.9, however in a peptide the pK_a is highly dependent on the local environment. A pK_a as high as 14 is not at all uncommon. Aspartate is pervasive in biosynthesis. As with all amino acids, the presence of acid protons depends on the residue's local chemical environment and the pH of the solution.

Discovery [edit]

Aspartic acid was first discovered in 1827 by Plisson, derived from asparagine, which had been isolated from asparagus juice in 1806, by boiling with a base.^[4]

Forms and nomenclature [edit]

There are two forms or enantiomers of aspartic acid. The name "aspartic acid" can refer to either enantiomer or a mixture of two.^[3] Of these two forms, only one, "L-aspartic acid", is directly incorporated into proteins. The biological roles of its counterpart, "D-aspartic acid" are more limited. Where enzymatic synthesis will produce one or the other, most chemical syntheses will produce both forms, "DL-aspartic acid," known as a racemic mixture.

Role in biosynthesis of amino acids [edit]

Aspartate is non-essential in mammals, being produced from oxaloacetate by transamination. It can also be generated from ornithine and citrulline in the urea cycle. In plants and microorganisms, aspartate is the precursor to several amino acids, including four that are essential for humans: methionine, threonine, isoleucine, and lysine. The conversion of aspartate to these other amino acids begins with reduction of aspartate to its "semialdehyde," O₂CCH(NH₂)CH₂CHO.^[5] Asparagine is derived from aspartate via transamidation:

-O₂CCH(NH₂)CH₂CO₂- + GC(O)NH₃+ O₂CCH(NH₂)CH₂CONH₃+ + GC(O)O

(where GC(O)NH₂ and GC(O)OH are glutamine and glutamic acid, respectively)

Other biochemical roles [edit]

Aspartate is also a metabolite in the urea cycle and participates in gluconeogenesis. It carries reducing equivalents in the malate-aspartate shuttle, which utilizes the ready interconversion of aspartate and oxaloacetate, which is the oxidized (dehydrogenated) derivative of malic acid. Aspartate donates one nitrogen atom in the biosynthesis of inosine, the precursor to the purine bases. In addition, aspartic acid acts as hydrogen acceptor in a chain of ATP synthase.

Interactive pathway map [edit]

Click on genes, proteins and metabolites below to link to respective articles. ^{[§ 1]}

[[File:

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

[[

]]

|{{{bSize}}}px]]

Glycolysis and Gluconeogenesis edit

1. ^ The interactive pathway map can be edited at WikiPathways: "GlycolysisGluconeogenesis_WP534". 

Neurotransmitter [edit]

Aspartate (the conjugate base of aspartic acid) stimulates NMDA receptors, though not as strongly as the amino acid neurotransmitter glutamate does.^[6]

Sources [edit]

Dietary sources [edit]

Aspartic acid is not an essential amino acid, which means that it can be synthesized from central metabolic pathway intermediates in humans. Aspartic acid is found in:

• Animal sources: luncheon meats, sausage meat, wild game
• Vegetable sources: sprouting seeds, oat flakes, avocado, asparagus^{[citation needed]}, young sugarcane, and molasses from sugar beets.^[1]
• Dietary supplements, either as aspartic acid itself or salts (such as magnesium aspartate)

Chemical synthesis [edit]

Racemic aspartic acid can be synthesized from diethyl sodium phthalimidomalonate, (C₆H₄(CO)₂NC(CO₂Et)₂).^[7]

The major disadvantage of the above technique is that equimolar amounts of each enantiomer are made, but the body only utilizes L-amino acids. Using biotechnology it is now possible to use immobilised enzymes to create just one type of enantiomer owing to their stereospecificity. Aspartic acid is made synthetically using ammonium fumarate and aspartase from E.coli, E.coli usually breaks down the aspartic acid as a nitrogen source but using excess amounts of ammonium fumarate a reversal of the enzyme's job is possible, and so aspartic acid is made to very high yields, 98.7 mM from 1 M.

See also [edit]

• Aspartate transaminase
• Polyaspartic acid
• Sodium poly(aspartate), a synthetic polyamide

References [edit]

External links [edit]

• American Chemical Society (21 April 2010). "Ancestral Eve' Crystal May Explain Origin of Life's Left-Handedness". ScienceDaily. Archived from the original on 23 April 2010. Retrieved 2010-04-21. 

v t e The 20 common amino acids General topics Protein Peptide Genetic code By properties Aliphatic Branched-chain amino acids (Valine Isoleucine Leucine) Methionine Alanine Proline Glycine Aromatic Phenylalanine Tyrosine Tryptophan Histidine Polar, uncharged Asparagine Glutamine Serine Threonine Positive charge (pKa) Lysine (≈10.8) Arginine (≈12.5) Histidine (≈6.1) Negative charge (pKa) Aspartic acid (≈3.9) Glutamic acid (≈4.1) Cysteine (≈8.3) Tyrosine (≈10.1) Other classifications Essential amino acids Ketogenic amino acid Glucogenic amino acid biochemical families: carbohydrates alcohols glycoproteins glycosides lipids eicosanoids fatty acids / intermediates phospholipids sphingolipids steroids nucleic acids constituents / intermediates proteins amino acids / intermediates tetrapyrroles / intermediates