出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/03/20 21:37:02」(JST)
| Names | |
|---|---|
| IUPAC name
Threonine
|
|
| Other names
2-Amino-3-hydroxybutanoic acid
|
|
| Identifiers | |
|
CAS Registry Number
|
80-68-2 Y 72-19-5 (L-isomer) |
| ChEBI | CHEBI:57926 Y |
| ChEMBL | ChEMBL291747 Y |
| ChemSpider | 6051 Y |
| DrugBank | DB00156 Y |
| EC number | 201-300-6 |
|
InChI
|
|
| Jmol-3D images | Image |
| PubChem | 6288 |
|
SMILES
|
|
| Properties | |
|
Molecular formula
|
C4H9NO3 |
| Molar mass | 119.12 g·mol−1 |
|
Solubility in water
|
(H2O, g/dl) 10.6(30°),14.1(52°),19.0(61°) |
| Acidity (pKa) | 2.63 (carboxyl), 10.43 (amino)[1] |
| Supplementary data page | |
|
Structure and
properties |
Refractive index (n), Dielectric constant (εr), etc. |
|
Thermodynamic
data |
Phase behaviour solid–liquid–gas |
|
Spectral data
|
UV, IR, NMR, MS |
|
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
|
|
| Y verify (what is: Y/N?) | |
| Infobox references | |
Threonine (abbreviated as Thr or T)[2] is an α-amino acid with the chemical formula HO2CCH(NH2)CH(OH)CH3. Its codons are ACU, ACA, ACC, and ACG. This essential amino acid is classified as polar. Together with serine, threonine is one of two proteinogenic amino acids bearing an alcohol group (tyrosine is not an alcohol but a phenol, since its hydroxyl group is bonded directly to an aromatic ring, giving it different acid/base and oxidative properties). It is also one of two common amino acids that bear a chiral side chain, along with isoleucine.
The threonine residue is susceptible to numerous posttranslational modifications. The hydroxyl side-chain can undergo O-linked glycosylation. In addition, threonine residues undergo phosphorylation through the action of a threonine kinase. In its phosphorylated form, it can be referred to as phosphothreonine.
It is a precursor of glycine, and can be used as a prodrug to reliably elevate brain glycine levels.
Threonine was discovered as the last of the 20 common proteinogenic amino acids in the 1930s by William Cumming Rose.
| |
| L-Threonine (2S,3R) and D-Threonine (2R,3S) |
| |
| L-allo-Threonine (2S,3S) and D-allo-Threonine (2R,3R) |
Threonine is one of two proteinogenic amino acids with two chiral centers. Threonine can exist in four possible stereoisomers with the following configurations: (2S,3R), (2R,3S), (2S,3S) and (2R,3R). However, the name L-threonine is used for one single diastereomer, (2S,3R)-2-amino-3-hydroxybutanoic acid. The second stereoisomer (2S,3S), which is rarely present in nature, is called L-allo-threonine. The two stereoisomers (2R,3S)- and (2R,3R)-2-amino-3-hydroxybutanoic acid are only of minor importance.[citation needed]
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 and homoserine. Homoserine undergoes O-phosphorylation; this phosphate ester undergoes hydrolysis concomitant with relocation of the OH group.[3] Enzymes involved in a typical biosynthesis of threonine include:
Threonine is metabolized in two ways:
Foods high in threonine include cottage cheese, poultry, fish, meat, lentils, Black turtle bean[4] and Sesame seeds.[5]
Racemic threonine can be prepared from crotonic acid by alpha-functionalization using mercury(II) acetate.[6]
|
|||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||
全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.
| リンク元 | 「スレオニン」「L-スレオニン」 |
| 関連記事 | 「L」「threonine」 |
-CH(CH3)-OH
-CH(CH3)-O-H2PO3