Norleucine

Chemical compound From Wikipedia, the free encyclopedia

Norleucine[a] (abbreviated as Nle) is an amino acid with the formula CH3(CH2)3CH(NH2)CO2H. 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.

Quick facts Names, Identifiers ...
Norleucine
Names
Preferred IUPAC name
(2S)-2-Aminohexanoic acid
Other names
Caprine
Glycoleucine
Identifiers
3D model (JSmol)
1721748
ChEBI
ChemSpider
DrugBank
ECHA InfoCard 100.009.512 Edit this at Wikidata
EC Number
  • 210-462-7
464584
KEGG
MeSH Norleucine
RTECS number
  • RC6308000
UNII
  • InChI=1S/C6H13NO2/c1-2-3-4-5(7)6(8)9/h5H,2-4,7H2,1H3,(H,8,9)
    Key: LRQKBLKVPFOOQJ-UHFFFAOYSA-N
  • CCCCC(N)C(O)=O
Properties
C6H13NO2
Molar mass 131.175 g·mol−1
Melting point 301 Â°C (574 Â°F; 574 K) (decomposes) [1]
16 g/L at 23 °C [2]
Acidity (pKa) 2.39 (carboxyl), 9.76 (amino)[3]
Related compounds
Related Aminoacids
 Norvaline (2-amino-pentanoic)
Aminocaproic acid (6-amino-hexanoic)
Leucine (2-amino-4-methyl-pentanoic)
Isoleucine (2-amino-3-methyl-pentanoic)
Lysine (2,6-diamino-hexanoic)
Related compounds
 Caproic acid (hexanoic)
Except where otherwise noted, data are given for materials in their standard state (at 25 Â°C [77 Â°F], 100 kPa).
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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 arises 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.[6]

Uses

It is nearly isosteric with methionine, even though it does not contain sulfur.[7] For this reason, 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.[8]

See also

  • Leucines, description of the isomers of leucine
  • norvaline, isomer of valine that has similar biochemistry to that of norleucine.

Notes

  1. [a]
    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.[4][5]

References

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