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Norleucine

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Norleucine
Names
IUPAC name (2S)-2-Aminohexanoic acid
Other names Caprine
Glycoleucine
Identifiers
CAS Number
3D model (JSmol)
Beilstein Reference 1721748
ChEBI
ChemSpider
DrugBank
ECHA InfoCard 100.009.512 Edit this at Wikidata
EC Number
  • 210-462-7
Gmelin Reference 464584
KEGG
MeSH Norleucine
PubChem CID
RTECS number
  • RC6308000
UNII
CompTox Dashboard (EPA)
InChI
  • InChI=1S/C6H13NO2/c1-2-3-4-5(7)6(8)9/h5H,2-4,7H2,1H3,(H,8,9)Key: LRQKBLKVPFOOQJ-UHFFFAOYSA-N
SMILES
  • CCCCC(N)C(O)=O
Properties
Chemical formula C6H13NO2
Molar mass 131.175 g·mol
Melting point 301 °C (decomposes)
Solubility in water 16 g/l at 23 °C
Acidity (pKa) 2.39 (carboxyl), 9.76 (amino)
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). checkY verify (what is  ?) Infobox references
Chemical compound

Norleucine (abbreviated as Nle) is an amino acid with the formula CH3(CH2)3CH(NH2)CO2H (nonzwitterionic formula). A systematic name for this compound is 2-aminohexanoic acid. The compound is an isomer of the more common amino acid leucine. Like most other α-amino acids, norleucine is chiral. It is a white water soluble solid.

Occurrence

Together with norvaline, norleucine is found in small amounts in some bacterial strains where its concentration can approach millimolar. Its biosynthesis has been examined. It arise via the action of 2-isopropylmalate synthase]] on α-ketobutyrate. The incorporation of Nle into peptides reflects the imperfect selectivity of the associated aminoacyl-tRNA synthetase. In Miller–Urey experiments probing prebiotic synthesis of amino acids, norleucine and especially norvaline are formed.

Uses

It is nearly isosteric methionine, even it does not contain sulfur. For example norleucine has been used to probe the role of methionine in Amyloid-β peptide (AβP) the central constituent of senile plaques in Alzheimer's disease. A study showed that with the substitution of the methionine at the 35 position with norleucine the neurotoxic effects of the Aβ peptides were completely negated.

See also

  • Leucines, description of the isomers of leucine

References

  1. Hermann Römpp, Jürgen Falbe und Manfred Regitz: Römpp Lexikon Chemie, 9. Auflage, Georg Thieme Verlag, Stuttgart 1992.
  2. Sicherheitsdatenblatt Acros.
  3. Dawson, R.M.C., et al., Data for Biochemical Research, Oxford, Clarendon Press, 1959.
  4. The use of the name norleucine is discouraged as it is a misnomer, given than nor is defined for an amino acid with one less methylene group than found in the proteinogenic form. "Nomenclature and Symbolism For Amino Acids and Peptides". Pure and Applied Chemistry. 56 (5): 595–624. 1984.
  5. Alvarez-Carreno, Claudia; Becerra, Arturo; Lazcano, Antonio "Norvaline and Norleucine May Have Been More Abundant Protein Components during Early Stages of Cell Evolution" Origins of Life and Evolution of Biospheres 2014, volume 43, 363-375. doi:10.1007/s11084-013-9344-3
  6. Moroder, Luis "Isosteric replacement of sulfur with other chalcogens in peptides and proteins" Journal of Peptide Science 2005, volume 11, 187-214. doi:10.1002/psc.654
  7. Clementi, ME and Misiti, F (2005 Nov). "Substitution of methionine 35 inhibits apoptotic effects of Abeta(31-35) and Abeta(25-35) fragments of amyloid-beta protein in PC12 cells". Med Sci Monit. 11 (11): BR381-5. PMID 16258386. {{cite journal}}: Check date values in: |date= (help)CS1 maint: multiple names: authors list (link)
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