Threonine

Threonine
Skeletal formula
Skeletal formula of L-threonine
Ball-and-stick model
Ball-and-stick model
Space-filling model
Space-filling model
Names
IUPAC name
Threonine
Other names
2-Amino-3-hydroxybutanoic acid
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.000.704 Edit this at Wikidata
EC Number
  • L: 200-774-1
KEGG
UNII
  • InChI=1S/C4H9NO3/c1-2(6)3(5)4(7)8/h2-3,6H,5H2,1H3,(H,7,8)/t2-,3+/m1/s1 checkY
    Key: AYFVYJQAPQTCCC-GBXIJSLDSA-N checkY
  • D/L: Key: AYFVYJQAPQTCCC-FGNFWGHYNA-N
  • L: C[C@H]([C@@H](C(=O)O)N)O
  • L Zwitterion: C[C@H]([C@@H](C(=O)[O-])[NH3+])O
Properties
C4H9NO3
Molar mass 119.120 g·mol−1
(H2O, g/dl) 10.6(30°),14.1(52°),19.0(61°)
Acidity (pKa) 2.63 (carboxyl), 10.43 (amino)[1]
Supplementary data page
Threonine (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Threonine (symbol Thr or T)[2] is an amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH+
3
form when dissolved in water), a carboxyl group (which is in the deprotonated −COO form when dissolved in water), and a side chain containing a hydroxyl group, making it a polar, uncharged amino acid. It is essential in humans, meaning the body cannot synthesize it: it must be obtained from the diet. Threonine is synthesized from aspartate in bacteria such as E. coli.[3] It is encoded by all the codons starting AC (ACU, ACC, ACA, and ACG).

Threonine sidechains are often hydrogen bonded; the most common small motifs formed are based on interactions with serine: ST turns, ST motifs (often at the beginning of alpha helices) and ST staples (usually at the middle of alpha helices).

  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 Joint Commission on Biochemical Nomenclature. 1983. Archived from the original on 9 October 2008. Retrieved 5 March 2018.
  3. ^ Raïs, Badr; Chassagnole, Christophe; Lettelier, Thierry; Fell, David; Mazat, Jean-Pierre (2001). "Threonine synthesis from aspartate in Escherichia coli cell-free extracts: pathway dynamics". Biochem J. 356 (Pt 2): 425–32. doi:10.1042/bj3560425. PMC 1221853. PMID 11368769.