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Valine
IUPAC name	Valine
Other names	2-amino-3-methylbutanoic acid
Identifiers
CAS number	516-06-3 ,; 72-18-4 (L-isomer); 640-68-6 (D-isomer)
PubChem	1182
EC-number	208-220-0
SMILES	CC(C)C(N)C(=O)O
Properties
Molecular formula	C5H11NO2
Molar mass	117.15 g mol−1
Density	1.316 g/cm3
Melting point	298 ºC decomp.
Solubility in water	soluble
Supplementary data page
Structure and; properties	n, εr, etc.
Thermodynamic; data	Phase behaviour; Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
	(what is this?) (verify); 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)^[2] 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.

[edit] 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-ketovalerate undergoes reductive amination with glutamate. Enzymes involved in this biosynthesis include:^[3]

Acetolactate synthase (also known as acetohydroxy acid synthase)
Acetohydroxy acid isomeroreductase
Dihydroxyacid dehydratase
Valine aminotransferase

[edit] Synthesis

Racemic valine can be synthesized by bromination of isovaleric acid followed by amination of the α-bromo derivative^[4]

HO₂CCH₂CH(CH₃)₂ + Br₂ → HO₂CCHBrCH(CH₃)₂ + HBr

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

[edit] References

^ 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 .
^ "Nomenclature and symbolism for amino acids and peptides (IUPAC-IUB Recommendations 1983)", Pure Appl. Chem. 56 (5): 595–624, 1984, doi:10.1351/pac198456050595 .
^ 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 .
^ Marvel, C. S. (1940), "dl-Valine", Org. Synth. 20: 106, http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV3P0848 ; Coll. Vol. 3: 848 .

[edit] External links

Isoleucine and valine biosynthesis

This biochemistry article is a stub. You can help Wikipedia by expanding it.

[0] 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 .

[1] "Nomenclature and symbolism for amino acids and peptides (IUPAC-IUB Recommendations 1983)", Pure Appl. Chem. 56 (5): 595–624, 1984, doi:10.1351/pac198456050595 .

[2] 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 .

[3] Marvel, C. S. (1940), "dl-Valine", Org. Synth. 20: 106, http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV3P0848 ; Coll. Vol. 3: 848 .

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Contents

[edit] Biosynthesis

[edit] Synthesis

[edit] References

[edit] External links