- Threonine
NatOrganicBox
name=(2"S",3"R")-2-Amino-3-hydroxybutanoic acid
PubChem = 6288
CAS = 72-19-5
EINECS = 200-774-1
SMILES = C [C@@H] (O) [C@H] (N)C(O)=O
C=4 | H=9 | N=1 | O=3
mass=119.12 g/molThreonine (abbreviated as Thr or T) [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] is an α-
amino acid with thechemical formula HO2CCH(NH2)CH(OH)CH3. Itscodon s are ACU, ACA, ACC, and ACG. Thisessential amino acid is classified as polar. Together withserine andtyrosine , threonine is one of three proteinogenic amino acids bearing an alcohol group.The threonine residue is susceptible to numerous
posttranslational modification s. The hydroxyside chain can undergo O-linkedglycosylation . In addition, threonine residues undergophosphorylation through the action of a threoninekinase . In its phosphorylated form, it can be referred to as phosphothreonine.Allo-threonine
With two chiral centers, threonine can exist in four possible
stereoisomer s, or two possiblediastereomer s of L-threonine. However, the name L-threonine is used for one singleenantiomer , (2"S",3"R")-2-amino-3-hydroxybutanoic acid. The second diastereomer (2"S",3"S"), which is rarely present in nature, is called L-"allo"-threonine.Biosynthesis
As an essential amino acid, threonine is not synthesized in humans, hence we must ingest threonine in the form of threonine-containing proteins. In plants and microorganisms, threonine is synthesized from
aspartic acid via α-aspartyl-semialdehyde andhomoserine . Homoserine undergoes "O"-phosphorylation; this phosphateester undergoes hydrolysis concomitant with relocation of the OH group. [Nelson, D. L.; Cox, M. M. "Lehninger, Principles of Biochemistry" 3rd Ed. Worth Publishing: New York, 2000. ISBN 1-57259-153-6.] Enzymes involved in a typical biosynthesis of threonine include:
#aspartokinase
# α-aspartate semialdehydedehydrogenase
# homoserine dehydrogenase
# homoserinekinase
# threoninesynthase .Metabolism
Threonine is metabolized in two ways:
* It is converted topyruvate viathreonine dehydrogenase . An intermediate in this pathway can undergo thiolysis with CoA to produceAcetyl-CoA andglycine .
* In humans, it is converted toalpha-ketobutyrate in a less common pathway via the enzymeserine dehydratase , and thereby enters the pathway leading tosuccinyl-CoA .ources
Foods high in threonine include
cottage cheese ,poultry ,fish ,meat ,lentil s, and sesame seeds.Fact|date=June 2007Racemic threonine can be prepared fromcrotonic acid by alpha-functionalization usingmercury(II) acetate . [OrgSynth | author = Carter, H. E.; West, H. D. | title = dl-Threonine | collvol = 3 | collvolpages = 813 | year = 1955 | prep = cv3p0813]References
ee also
*
Harold Dadford West American Biochemist who first synthetised the Threonine.External links
* [http://www.chem.qmul.ac.uk/iubmb/enzyme/reaction/AminoAcid/Thr.html Threonine biosynthesis]
* [http://www.compchemwiki.org/index.php?title=Threonine Computational Chemistry Wiki]
* [http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=205 CID 205]
* [http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=6288 CID 6288]
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См. также в других словарях:
Threonine — Thréonine Thréonine Formule semi développée de la L thréonine. Général No CAS … Wikipédia en Français
Thréonine — L thréonine (2S,3R) et L allo thréonine (2S,3S) … Wikipédia en Français
thréonine — [ treɔnin ] n. f. • apr. 1935; angl. threonine, de threose mot all., altér. de erythrose, et ine ♦ Biochim. Acide aminé essentiel, possédant une fonction alcool secondaire, l un des principaux constituants des protéines. ● thréonine nom féminin… … Encyclopédie Universelle
threonine — threonine. См. треонин. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) … Молекулярная биология и генетика. Толковый словарь.
threonine — [thrē′ə nēn΄, thrē′ənin] n. [prob. < threon(ic acid) + INE3] an essential amino acid, CH3CH(OH)CH(NH2)COOH, obtained from the hydrolysis of many proteins … English World dictionary
threonine — /three euh neen , nin/, n. Biochem. an essential amino acid, CH3CHOHCH(NH2)COOH, obtained by the hydrolysis of proteins. Abbr.: Thr; Symbol: T [1925 30; threon (alter. of Gk erythrón, neut. of erythrós red; see ERYTHRO ) + INE2] * * * One of the… … Universalium
threonine — 2 Amino 3 hydroxybutyric acid; the l isomer is one of the naturally occurring amino acid s, included in the structure of most proteins, and nutritionally essential in the diet of humans and other mammals. t. deaminase SYN: t. dehydratase. t.… … Medical dictionary
threonine — treoninas statusas T sritis chemija formulė CH₃CH(OH)CH(NH₂)COOH santrumpa( os) Thr, T atitikmenys: angl. threonine rus. треонин ryšiai: sinonimas – 2 amino 3 hidroksibutano rūgštis … Chemijos terminų aiškinamasis žodynas
threonine — noun Etymology: probably from threonic acid (C4H8O5) Date: 1936 a colorless crystalline essential amino acid C4H9NO3 … New Collegiate Dictionary
threonine — (= Thr; T; 119 D) The hydroxylated polar amino acid … Dictionary of molecular biology