Aspartic acid 63540 219661705 2008-06-16T08:40:43Z 68.45.219.63 It's capability of excitotoxicity works the same way of glutamate if the NMDA receptors are over stimulated by these transmitters {{NatOrganicBox | image= [[Image:Asparaginsäure - Aspartic acid.svg|200px|Structural formula of aspartic acid]]<br><br>[[Image:L-aspartic-acid-3D-sticks2.png|200px|3D stick model of aspartic acid]]<br />Chemical structure of L-aspartic acid | name=(2S)-2-aminobutanedioic acid | PubChem = 5960 | CAS = 56-84-8 | SMILES = N[C@@H](CC(O)=O)C(O)=O | C=4 | H=7 | N=1 | O=4 | mass=133.10 g/mol }} '''Aspartic acid''' (abbreviated as '''Asp''' or '''D'''; '''Asx''' or '''B''' represent either aspartic acid or [[asparagine]])<ref>{{cite web | author=IUPAC-IUBMB Joint Commission on Biochemical Nomenclature | title=Nomenclature and Symbolism for Amino Acids and Peptides | work=Recommendations on Organic & Biochemical Nomenclature, Symbols & Terminology etc | url=http://www.chem.qmul.ac.uk/iupac/AminoAcid/ | accessdate=2007-05-17}}</ref> is an α-[[amino acid]] with the [[chemical formula]] HO<sub>2</sub>CCH(NH<sub>2</sub>)CH<sub>2</sub>CO<sub>2</sub>H. The [[carboxylate anion]] 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 [[protein]]s. Its [[codon]]s are GAU and GAC. Aspartic acid is, together with [[glutamic acid]], classified as an acidic amino acid with a [[pKa]] of 4.0. Aspartic acid is pervasive in biosynthesis. As with all amino acids, the location of acid protons depends on the pH of the solution and the crystallization conditions. ==Role in biosynthesis of amino acids== Aspartic acid is non-essential in [[mammal]]s, being produced from [[oxaloacetate]] by [[transamination]]. In plants and microorganisms, aspartic acid is the precursor to several amino acids, including four that are essential: [[methionine]], [[threonine]], [[isoleucine]], and [[lysine]]. The conversion of aspartic acid to these other amino acids begins with reduction of aspartic acid to its "semialdehyde," HO<sub>2</sub>CCH(NH<sub>2</sub>)CH<sub>2</sub>CHO.<ref>Nelson, D. L.; Cox, M. M. "Lehninger, Principles of Biochemistry" 3rd Ed. Worth Publishing: New York, 2000. ISBN 1-57259-153-6.</ref> [[Asparagine]] is derived from aspartic acid via transamidation: :HO<sub>2</sub>CCH(NH<sub>2</sub>)CH<sub>2</sub>CO<sub>2</sub>H + ''G''C(O)NH<sub>2</sub> HO<sub>2</sub>CCH(NH<sub>2</sub>)CH<sub>2</sub>CONH<sub>2</sub> + ''G''C(O)OH (where ''G''C(O)NH<sub>2</sub> and ''G''C(O)OH are [[glutamine]] and [[glutamic acid]], respectively) ==Other biochemical roles== Aspartic acid 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. Aspartic acid donates one nitrogen atom in the biosynthesis of [[inositol]], the precursor to the [[purine]] bases. ====Neurotransmitter==== Aspartate (the [[conjugate base]] of aspartic acid) stimulates [[NMDA receptor]]s, though not as strongly as the amino acid neurotransmitter [[glutamic acid|glutamate]] does.<ref>Philip E. Chen, Matthew T. Geballe, Phillip J. Stansfeld, Alexander R. Johnston, Hongjie Yuan, Amanda L. Jacob, James P. Snyder, Stephen F. Traynelis, and David J. A. Wyllie. 2005. [http://molpharm.aspetjournals.org/cgi/content/full/67/5/1470 Structural Features of the Glutamate Binding Site in Recombinant NR1/NR2A N-Methyl-D-aspartate Receptors Determined by Site-Directed Mutagenesis and Molecular Modeling]. ''Molecular Pharmacology''. Volume 67, Pages 1470-1484.</ref> It serves as an excitatory [[neurotransmitter]] in the brain and is an [[excitotoxin]]. As a neurotransmitter, aspartic acid may provide resistance to fatigue, and, thus, leads to endurance, although the evidence to support this idea is not strong.{{Fact|date=March 2008}} ==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''': luncheon meats, sausage meat, wild game * '''Vegetable sources''': sprouting seeds, oat flakes, [[avocado]], [[asparagus]]. ===Chemical Synthesis=== [[Racemic]] aspartic acid can be synthesized from diethyl sodium phthalimidomalonate, (C<sub>6</sub>H<sub>4</sub>(CO)<sub>2</sub>NC(CO<sub>2</sub>Et)<sub>2</sub>).<ref> Dunn, M. S.; Smart, B. W. “DL-Aspartic Acid”Organic Syntheses, Collected Volume 4, p.55 (1963). http://www.orgsyn.org/orgsyn/pdfs/CV4P0055.pdf</ref> ==References== {{Reflist}} ==See also== * [[Aspartate transaminase]] * [[Sodium poly(aspartate)]], a synthetic [[polyamide]] {{AminoAcids}} [[Category:Proteinogenic amino acids]] [[Category:Glucogenic amino acids]] [[Category:Acidic amino acids]] [[Category:Dicarboxylic acids]] [[Category:Neurotransmitters]] [[bn:অ্যাস্পার্টিক অ্যাসিড]] [[ca:Àcid aspàrtic]] [[cs:Kyselina asparagová]] [[de:Asparaginsäure]] [[es:Ácido aspártico]] [[eo:Asparta acido]] [[fr:Acide aspartique]] [[ko:아스파르트산]] [[id:Asam aspartat]] [[it:Acido aspartico]] [[he:חומצה אספרטית]] [[lv:Asparagīnskābe]] [[lb:Aspartat]] [[lt:Asparto rūgštis]] [[hu:Aszparaginsav]] [[nl:Asparaginezuur]] [[ja:アスパラギン酸]] [[pl:Kwas asparaginowy]] [[pt:Ácido aspártico]] [[ru:Аспарагиновая кислота]] [[fi:Asparagiinihappo]] [[sv:Asparaginsyra]] [[tr:Aspartik asit]] [[uk:Аспарагінова кислота]] [[zh:天冬氨酸]]