Valine

Valine

NatOrganicBox


name=("S")-2-amino-3-methyl-butanoic acid
PubChem = 1182
CAS = 72-18-4
SMILES = CC(C)C(N)C(=O)O
C=5 | H=11 | N=1 | O=2
mass=117.15 g/mol

Valine (abbreviated as Val or V) [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 the chemical formula HO2CCH(NH2)CH(CH3)2. L-Valine is one of 20 proteogenic amino acids. Its codons are GUU, GUC, GUA, and GUG. This essential amino acid is classified as nonpolar. 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.

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: [Nelson, D. L.; Cox, M. M. "Lehninger, Principles of Biochemistry" 3rd Ed. Worth Publishing: New York, 2000. ISNB 1-57259-153-6.]
# Acetolactate synthase (also known as acetohydroxy acid synthase)
# Acetohydroxy acid isomeroreductase
# Dihydroxyacid dehydratase
# Valine aminotransferase

ynthesis

Racemic valine can be synthesized by bromination of isovaleric acid followed by amination of the α-bromo derivative [Marvel, C. S. “d,l-Valine” Organic Syntheses, Collected Volume 3, p.848 (1955). http://www.orgsyn.org/orgsyn/pdfs/CV3P0848.pdf] :HO2CCH2CH(CH3)2 + Br2 → HO2CCHBrCH(CH3)2 + HBr:HO2CCHBrCH(CH3)2 + 2 NH3 → HO2CCH(NH2)CH(CH3)2 + NH4Br

Dietary aspects

Nutritional sources of valine include cottage cheese, fish, poultry, peanuts, sesame seeds, and lentils.

References

External links

* [http://www.chem.qmul.ac.uk/iubmb/enzyme/reaction/AminoAcid/IleVal.html Isoleucine and valine biosynthesis]


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  • valine — [ valin ] n. f. • 1907; all. Valin; de val(érique) et (am)ine ♦ Biochim. Acide aminé essentiel, l un des vingt constituants des protéines. ● valine nom féminin Acide aminé indispensable (c est à dire non synthétisable par l organisme, qui doit le …   Encyclopédie Universelle

  • valine — valine. См. валин. (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.

  • valine — [val′ēn, val′in; vā′lēn, vā′lin] n. [< (iso)val(eric acid) + INE3] a white, crystalline, essential amino acid, (CH3) 2CHCH(NH2)COOH, found in small quantities in many proteins: see AMINO ACID …   English World dictionary

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  • Valine — Als Valine fasst man die drei isomeren Aminosäuren Valin, Norvalin und Isovalin zusammen. Valin und Norvalin kann man als propylsubstituierte Glycine auffassen. Auffallend ist jedoch das Isovalin, wo hier eine Methylgruppe direkt am α… …   Deutsch Wikipedia

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  • valine — nor·valine; valine; …   English syllables

  • valine — 2 Amino 3 methylbutanoic acid; the l isomer is a constituent of most proteins; a nutritionally essential amino acid. * * * va·line vā .lēn, va .lēn n a crystalline essential amino acid C5H11NO2 that occurs esp. in fibrous proteins abbr. Val * * * …   Medical dictionary

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  • Valine-3-methyl-2-oxovalerate transaminase — In enzymology, a valine 3 methyl 2 oxovalerate transaminase (EC number|2.6.1.32) is an enzyme that catalyzes the chemical reaction:L valine + (S) 3 methyl 2 oxopentanoate ightleftharpoons 3 methyl 2 oxobutanoate + L isoleucineThus, the two… …   Wikipedia

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