Asparagine

L-Asparagine
Identifiers
CAS number 70-47-3 YesY
PubChem 236
ChemSpider 6031 YesY
UNII 7NG0A2TUHQ YesY
EC-number 200-735-9
DrugBank DB03943
KEGG C00152 YesY
ChEBI CHEBI:17196 YesY
ChEMBL CHEMBL58832 YesY
Jmol-3D images Image 1
Image 2
Properties
Molecular formula C4H8N2O3
Molar mass 132.12 g mol−1
Acidity (pKa) 2.02 (carboxyl), 8.8 (amino)[1]
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Asparagine (abbreviated as Asn or N; Asx or B represent either asparagine or aspartic acid) is one of the 20 most common natural amino acids on Earth. It has carboxamide as the side-chain's functional group. It is not an essential amino acid. Its codons are AAU and AAC.[2]

A reaction between asparagine and reducing sugars or reactive carbonyls produces acrylamide (acrylic amide) in food when heated to sufficient temperature. These products occur in baked goods such as French fries, potato chips, and roasted coffee.

Contents

History

Asparagine was first isolated in 1806, under a crystalline form, by French chemists Louis Nicolas Vauquelin and Pierre Jean Robiquet (then a young assistant) from asparagus juice,[3][4] in which it is abundant — hence, the name they chose for that new matter — becoming the first amino acid to be isolated. The characteristic smell observed in the urine of individuals after their consumption of asparagus is attributed to various metabolic byproducts of asparagine.[5]

A few years later, in 1809, Pierre Jean Robiquet again identified, this time from liquorice root, a substance with properties he qualified as very similar to those of asparagine, that Plisson in 1828 identified as asparagine itself.[6]

Structural function in proteins

Since the asparagine side-chain can form hydrogen bond interactions with the peptide backbone, asparagine residues are often found near the beginning and the end of alpha-helices, and in turn motifs in beta sheets. Its role can be thought as "capping" the hydrogen bond interactions that would otherwise be satisfied by the polypeptide backbone. Glutamines, with an extra methylene group, have more conformational entropy and thus are less useful in this regard.

Asparagine also provides key sites for N-linked glycosylation, modification of the protein chain with the addition of carbohydrate chains.

Sources

Dietary sources

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

Biosynthesis

The precursor to asparagine is oxaloacetate. Oxaloacetate is converted to aspartate using a transaminase enzyme. The enzyme transfers the amino group from glutamate to oxaloacetate producing α-ketoglutarate and aspartate. The enzyme asparagine synthetase produces asparagine, AMP, glutamate, and pyrophosphate from aspartate, glutamine, and ATP. In the asparagine synthetase reaction, ATP is used to activate aspartate, forming β-aspartyl-AMP. Glutamine donates an ammonium group, which reacts with β-aspartyl-AMP to form asparagine and free AMP.

The biosynthesis of asparagine from oxaloacetate

Degradation

Aspartate is a glucogenic amino acid. L-asparaginase hydrolyzes the amide group to form aspartate and ammonium. A transaminase converts the aspartate to oxaloacetate, which can then be metabolized in the citric acid cycle or gluconeogenesis.

Function

The nervous system requires asparagine. It also plays an important role in the synthesis of ammonia.

Betaine structure

(S)-Asparagine (left) and (R)-asparagine (right) in zwitterionic form at neutral pH

References

  1. ^ Dawson, R.M.C., et al., Data for Biochemical Research, Oxford, Clarendon Press, 1959.
  2. ^ "Nomenclature and symbolism for amino acids and peptides (IUPAC-IUB Recommendations 1983)", Pure Appl. Chem. 56 (5): 595–624, 1984, doi:10.1351/pac198456050595 .
  3. ^ Vauquelin LN, Robiquet PJ (1806). "La découverte d'un nouveau principe végétal dans le suc des asperges". Annales de Chimie 57: 88–93. 
  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. http://books.google.com/?id=7JM8AAAAIAAJ&pg=PA112. Retrieved January 18, 2010. 
  5. ^ S.C. Mitchell (2001). "Food Idiosyncrasies: Beetroot and Asparagus". Drug Metabolism and Disposition 29 (4 Pt 2): 539–534. PMID 11259347. http://dmd.aspetjournals.org/content/29/4/539.full. Retrieved january 18, 2010. 
  6. ^ http://www.henriettesherbal.com/eclectic/kings/glycyrrhiza.html

External links


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Look at other dictionaries:

  • Asparagine — L ou S( ) asparagine D ou R(+) asparagine …   Wikipédia en Français

  • asparagine — [ asparaʒin ] n. f. • 1817; du rad. du lat. asparagus « asperge » ♦ Biochim. Acide aminé naturel, amide de l acide aspartique. ● asparagine nom féminin Amide de l acide aspartique, dont l une des trois formes, la l asparagine, fait partie des 20… …   Encyclopédie Universelle

  • Asparagine — As*par a*gine, n. [Cf. F. asparagine.] (Chem.) A white, nitrogenous, crystallizable substance, {C4H8N2O3+H2O}, found in many plants, and first obtained from asparagus. It is believed to aid in the disposition of nitrogenous matter throughout the… …   The Collaborative International Dictionary of English

  • asparagine — [as par′ə jēn΄, asper′jēn; as par′əjin΄] n. [Fr < L asparagus (see ASPARAGUS) + Fr ine, INE3] a nonessential amino acid, NH2COCH2CH(NH2)COOH …   English World dictionary

  • asparagine — (= b asparagine; Asn; N; 132D) …   Dictionary of molecular biology

  • asparagine — /euh spar euh jeen , jin/, n. a white, crystalline, amino acid, NH2COCH2CH(NH2)COOH, soluble in water, obtained from certain plants, esp. legumes, and used chiefly as a nutrient in culture media for certain bacteria. Abbr.: Asn; Symbol: N [1805… …   Universalium

  • asparagine — asparaginas statusas T sritis chemija formulė H₂NCOCH₂CH(NH₂)COOH santrumpa( os) Asn, N, Asp–NH₂ atitikmenys: angl. asparagine rus. аспарагин ryšiai: sinonimas – 2 amino 3 karbamoilpropano rūgštis …   Chemijos terminų aiškinamasis žodynas

  • asparagine — noun Etymology: French, from Latin asparagus Date: 1813 a nonessential amino acid C4H8N2O3 that is an amide of aspartic acid …   New Collegiate Dictionary

  • asparagine — noun A nonessential amino acid CHNO found in plants such as asparagus. Syn: Asn …   Wiktionary

  • asparagine — NH2COCH2CH(NH3+COO−; the β amide of aspartic acid, the l isomer is a nutritionally nonessential amino acid occurring in proteins; a diuretic. a. ligase an acid:ammonia ligase (amide synthetase) forming l a. and l glutamate from l aspartate and l… …   Medical dictionary


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