Aspartic acid

Aspartic acid
Names
	IUPAC names Trivial: Aspartic acid ; Systematic: 2-Aminobutanedioic acid
	Other names Aminosuccinic acid, asparagic acid, asparaginic acid
Identifiers
CAS Number	617-45-8 ;
3D model (JSmol)	Interactive image; Interactive image;
ChEBI	CHEBI:22660 ;
ChEMBL	ChEMBL139661 ;
ChemSpider	411 ;
ECHA InfoCard	100.000.265
KEGG	C16433 ;
PubChem CID	424;
UNII	28XF4669EP ;
CompTox Dashboard (EPA)	DTXSID7022621 ;
	InChI InChI=1S/C4H7NO4/c5-2(4(8)9)1-3(6)7/h2H,1,5H2,(H,6,7)(H,8,9) Key: CKLJMWTZIZZHCS-UHFFFAOYSA-N ; InChI=1/C4H7NO4/c5-2(4(8)9)1-3(6)7/h2H,1,5H2,(H,6,7)(H,8,9) Key: CKLJMWTZIZZHCS-UHFFFAOYAE;
	SMILES O=C(O)CC(N)C(=O)O; C(C(C(=O)O)N)C(=O)O;
Properties
Chemical formula	C4H7NO4
Molar mass	133.103 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
Acidity (pKa)	3.9
Hazards
NFPA 704 (fire diamond)	1 1 0
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). verify (what is ?) Infobox references

Aspartic acid (abbreviated as D-AA, Asp, or D)^[3] is an α-amino acid with the chemical formula HOOCCH(NH₂)CH₂COOH. The carboxylate anion and salts of aspartic acid are known as aspartate. The L-isomer of aspartate is one of the 23 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

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

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

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

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

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

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|alt=Glycolysis and Gluconeogenesis edit]]

Glycolysis and Gluconeogenesis edit

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

Neurotransmitter

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

Sources

Dietary sources

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: oysters, 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)
The sweetener aspartame (brands: NutraSweet, Equal, Canderel, etc.)

Chemical synthesis

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. 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 mmol from 1 mol.

References

^ ^a ^b "862. Aspartic acid". The Merck Index (11th ed.). 1989. p. 132. ISBN 0-911910-28-X.
^ http://www.inchem.org/documents/icsc/icsc/eics1439.htm
^ ^a ^b "Nomenclature and symbolism for amino acids and peptides (IUPAC-IUB Recommendations 1983)", Pure Appl. Chem., 56 (5): 595–624, 1984, doi:10.1351/pac198456050595.
^ R.H.A. Plimmer (1912) [1908]. R.H.A. Plimmer & F.G. Hopkins (ed.). The chemical composition of the proteins. Monographs on biochemistry. Vol. Part I. Analysis (2nd ed.). London: Longmans, Green and Co. p. 112. Retrieved January 18, 2010.
^ Lehninger, Albert L.; Nelson, David L.; Cox, Michael M. (2000). Principles of Biochemistry (3rd ed.). New York: W. H. Freeman. ISBN 1-57259-153-6..
^ Chen, Philip E.; Geballe, Matthew T.; Stansfeld, Phillip J.; Johnston, Alexander R.; Yuan, Hongjie; Jacob, Amanda L.; Snyder, James P.; Traynelis, Stephen F.; Wyllie, David J. A. (2005). "Structural Features of the Glutamate Binding Site in Recombinant NR1/NR2A N-Methyl-D-aspartate Receptors Determined by Site-Directed Mutagenesis and Molecular Modeling". Mol. Pharmacol. 67 (5): 1470–84. doi:10.1124/mol.104.008185. PMID 15703381. {{cite journal}}: Unknown parameter |displayauthors= ignored (|display-authors= suggested) (help)
^ Dunn, M. S.; Smart, B. W. (1950). "DL-Aspartic Acid". Organic Syntheses. 30: 7; Collected Volumes, vol. 4, p. 55..

External links

GMD MS Spectrum
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. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)

Template:B03, B05, B06

[WikiPathways-6] The interactive pathway map can be edited at WikiPathways: "GlycolysisGluconeogenesis_WP534".

[merck-1] "862. Aspartic acid". The Merck Index (11th ed.). 1989. p. 132. ISBN 0-911910-28-X.

[2] ttp://www.inchem.org/documents/icsc/icsc/eics1439.htm

[IUPAC-3] "Nomenclature and symbolism for amino acids and peptides (IUPAC-IUB Recommendations 1983)", Pure Appl. Chem., 56 (5): 595–624, 1984, doi:10.1351/pac198456050595.

[4] R.H.A. Plimmer (1912) [1908]. R.H.A. Plimmer & F.G. Hopkins (ed.). The chemical composition of the proteins. Monographs on biochemistry. Vol. Part I. Analysis (2nd ed.). London: Longmans, Green and Co. p. 112. Retrieved January 18, 2010.

[5] Lehninger, Albert L.; Nelson, David L.; Cox, Michael M. (2000). Principles of Biochemistry (3rd ed.). New York: W. H. Freeman. ISBN 1-57259-153-6..

[7] Chen, Philip E.; Geballe, Matthew T.; Stansfeld, Phillip J.; Johnston, Alexander R.; Yuan, Hongjie; Jacob, Amanda L.; Snyder, James P.; Traynelis, Stephen F.; Wyllie, David J. A. (2005). "Structural Features of the Glutamate Binding Site in Recombinant NR1/NR2A N-Methyl-D-aspartate Receptors Determined by Site-Directed Mutagenesis and Molecular Modeling". Mol. Pharmacol. 67 (5): 1470–84. doi:10.1124/mol.104.008185. PMID 15703381. {{cite journal}}: Unknown parameter |displayauthors= ignored (|display-authors= suggested) (help)

[8] Dunn, M. S.; Smart, B. W. (1950). "DL-Aspartic Acid". Organic Syntheses. 30: 7; Collected Volumes, vol. 4, p. 55..

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