Valine

Valine
IUPAC name

Valine
Other names

2-amino-3-methylbutanoic acid
Identifiers
CAS number 516-06-3 Y, 72-18-4 (L-isomer) Y, 640-68-6 (D-isomer) Y
PubChem 1182
ChemSpider 6050 Y
UNII 4CA13A832H Y
EC-number 208-220-0
DrugBank DB00161
KEGG D00039 Y
ChEBI CHEBI:57762 N
ChEMBL CHEMBL43068 Y
Jmol-3D images Image 1
Properties[2]
Molecular formula C5H11NO2
Molar mass 117.15 g mol−1
Density 1.316 g/cm3
Melting point

298 °C decomp.
Solubility in water soluble
Acidity (pKa) 2.32 (carboxyl), 9.62 (amino)[1]
Supplementary data page
Structure and
properties		 n, εr, etc.
Thermodynamic
data		 Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
 N (verify) (what is: Y/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Valine (abbreviated as Val or V)[3] is an α-amino acid with the chemical formula HO2CCH(NH2)CH(CH3)2. L-Valine is one of 20 proteinogenic amino acids. Its codons are GUU, GUC, GUA, and GUG. This essential amino acid is classified as nonpolar. Human dietary sources include cottage cheese, fish, poultry, peanuts, sesame seeds, and lentils.

Along with leucine and isoleucine, valine is a branched-chain amino acid. It is named after the plant valerian. In sickle-cell disease, valine substitutes for the hydrophilic amino acid glutamic acid in hemoglobin. Because valine is hydrophobic, the hemoglobin does not fold correctly.

Contents

Biosynthesis

Valine is an essential amino acid, hence it must be ingested, usually as a component of proteins. It is synthesized in plants via several steps starting from pyruvic acid. The initial part of the pathway also leads to leucine. The intermediate α-ketoisovalerate undergoes reductive amination with glutamate. Enzymes involved in this biosynthesis include:[4]

  1. Acetolactate synthase (also known as acetohydroxy acid synthase)
  2. Acetohydroxy acid isomeroreductase
  3. Dihydroxyacid dehydratase
  4. Valine aminotransferase

Synthesis

Racemic valine can be synthesized by bromination of isovaleric acid followed by amination of the α-bromo derivative[5]

HO2CCH2CH(CH3)2 + Br2 → HO2CCHBrCH(CH3)2 + HBr
HO2CCHBrCH(CH3)2 + 2 NH3 → HO2CCH(NH2)CH(CH3)2 + NH4Br

References

  1. ^ Dawson, R.M.C., et al., Data for Biochemical Research, Oxford, Clarendon Press, 1959.
  2. ^ Weast, Robert C., ed (1981). CRC Handbook of Chemistry and Physics (62nd ed.). Boca Raton, FL: CRC Press. p. C-569. ISBN 0-8493-0462-8. 
  3. ^ "Nomenclature and symbolism for amino acids and peptides (IUPAC-IUB Recommendations 1983)", Pure Appl. Chem. 56 (5): 595–624, 1984, doi:10.1351/pac198456050595 .
  4. ^ Lehninger, Albert L.; Nelson, David L.; Cox, Michael M. (2000), Principles of Biochemistry (3rd ed.), New York: W. H. Freeman, ISBN 1-57259-153-6 .
  5. ^ Marvel, C. S. (1940), "dl-Valine", Org. Synth. 20: 106, http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV3P0848 ; Coll. Vol. 3: 848 .

External links

By properties
Polar, uncharged
Positive charge (pKa)
Lysine (≈10.8) · Arginine (≈12.5) · Histidine (≈6.1)
Negative charge (pKa)
Aspartic acid (≈3.9) · Glutamic acid (≈4.1) · Cysteine (≈8.3) · Tyrosine (≈10.1)
General
Other classifications
biochemical families: prot · nucl · carb (glpr, alco, glys) · lipd (fata/i, phld, strd, gllp, eico) · amac/i · ncbs/i · ttpy/i
K→acetyl-CoA
G
other
valine→
Other

M: MET

mt, k, c/g/r/p/y/i, f/h/s/l/o/e, a/u, n, m

k, cgrp/y/i, f/h/s/l/o/e, au, n, m, epon

m(A16/C10),i(k, c/g/r/p/y/i, f/h/s/o/e, a/u, n, m)
biochemical families: prot · nucl · carb (glpr, alco, glys) · lipd (fata/i, phld, strd, gllp, eico) · amac/i · ncbs/i · ttpy/i