Aspartic acid

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Aspartic acid
Aspartic Acidph.png
Ball-and-stick model of the L-aspartic acid molecule as a zwitterion
Names
IUPAC names
Trivial: Aspartic acid
Systematic: 2-Aminobutanedioic acid
Other names
Aminosuccinic acid, asparagic acid, asparaginic acid[1]
Identifiers
617-45-8 YesY
56-84-8 (L-isomer) N
1783-96-6 (D-isomer) N
ChEBI CHEBI:22660 YesY
ChEMBL ChEMBL139661 YesY
ChemSpider 411 YesY
EC Number 200-291-6
Jmol 3D model Interactive image
Interactive image
KEGG C16433 YesY
PubChem 424
UNII 28XF4669EP YesY
Properties
C4H7NO4
Molar mass 133.10 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) 3.9
Hazards
Safety data sheet See: data page
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
Infobox references

Aspartic acid (abbreviated as Asp or D; encoded by the codons [GAU and GAC]), also known as aspartate, is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH+
3
form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −COO form under biological conditions), and a side chain CH2COOH. Under physiological conditions in proteins the sidechain usually occurs as the negatively charged aspartate form, −COO. It is semi-essential in humans, meaning the body can synthesize it from oxaloacetate.

In proteins aspartate sidechains are often hydrogen bonded, often as asx turns or asx motifs, which often occur at the N-termini of alpha helices.

Asp's L-isomer is one of the 23 proteinogenic amino acids, i.e., the building blocks of proteins. Asp (and glutamic acid) is classified as acidic, with a pKa of 3.9, however in a peptide this is highly dependent on the local environment (as with all amino acids), and could be as high as 14. Asp is pervasive in biosynthesis.

L-aspartic acid is one of the two main ingredients of the artificial sweetener aspartame, along with L-phenylalanine.

Discovery[edit]

Aspartic acid was first discovered in 1827 by Auguste-Arthur Plisson and Étienne Ossian Henry,[3] 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.[5] 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.

Metabolism[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.[6] 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]

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GlycolysisGluconeogenesis_WP534 go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to article go to Entrez go to article go to article go to article go to article go to article go to WikiPathways go to article go to Entrez go to article
|{{{bSize}}}px|alt=Glycolysis and Gluconeogenesis edit]]
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 L-glutamate does.[7]

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:

Chemical synthesis[edit]

Racemic aspartic acid can be synthesized from diethyl sodium phthalimidomalonate, (C6H4(CO)2NC(CO2Et)2).[10]

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.

See also[edit]

References[edit]

  1. ^ a b "862. Aspartic acid". The Merck Index (11th ed.). 1989. p. 132. ISBN 0-911910-28-X. 
  2. ^ "ICSC 1439 - L-ASPARTIC ACID". inchem.org. 
  3. ^ Berzelius, Jöns Jakob; Öngren, Olof Gustaf (1839). Traité de chimie (in French). 3. Brussels: A. Wahlen et Cie. p. 81. Retrieved 25 August 2015. 
  4. ^ R.H.A. Plimmer (1912) [1908]. R.H.A. Plimmer & F.G. Hopkins, ed. The chemical composition of the proteins. Monographs on biochemistry. Part I. Analysis (2nd ed.). London: Longmans, Green and Co. p. 112. Retrieved January 18, 2010. 
  5. ^ "Nomenclature and symbolism for amino acids and peptides (IUPAC-IUB Recommendations 1983)", Pure Appl. Chem., 56 (5): 595–624, 1984, doi:10.1351/pac198456050595 .
  6. ^ 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. 
  8. ^ D. K. Salunkhe; S.S. Kadam (18 August 1995). Handbook of Fruit Science and Technology: Production, Composition, Storage, and Processing. CRC Press. pp. 368–. ISBN 978-0-8247-9643-3. 
  9. ^ Douglas M. Considine (6 December 2012). Foods and Food Production Encyclopedia. Springer Science & Business Media. pp. 114–. ISBN 978-1-4684-8511-0. 
  10. ^ Dunn, M. S.; Smart, B. W. (1950). "DL-Aspartic Acid". Org. Synth. 30: 7. ; Coll. Vol., 4, p. 55 .

External links[edit]