Valine

Jump to: navigation, search
Skeletal formula of valine
3D stick model of valine molecule

Valine

Systematic (IUPAC) name
(S)-2-amino-3-methyl-butanoic acid
Identifiers
CAS number 72-18-4
PubChem         1182
Chemical data
Formula C5H11NO2 
Molar mass 117.15 g/mol
SMILES CC(C)C(N)C(=O)O
Complete data

Valine (abbreviated as Val or V)[1] 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:[2]

  1. acetolactate 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[3]

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

  1. IUPAC-IUBMB Joint Commission on Biochemical Nomenclature. "Nomenclature and Symbolism for Amino Acids and Peptides". Recommendations on Organic & Biochemical Nomenclature, Symbols & Terminology etc. Retrieved 2007-05-17. 
  2. Nelson, D. L.; Cox, M. M. "Lehninger, Principles of Biochemistry" 3rd Ed. Worth Publishing: New York, 2000. ISNB 1-57259-153-6.
  3. Marvel, C. S. “d,l-Valine” Organic Syntheses, Collected Volume 3, p.848 (1955). http://www.orgsyn.org/orgsyn/pdfs/CV3P0848.pdf

External links


<tr bgcolor="#ccccff"><td colspan="3" align="center">
v  d  e
Major families of biochemicals</td></tr><tr><td colspan="3" style="text-align: center;">Peptides | Amino acids | Nucleic acids | Carbohydrates | Nucleotide sugars | Lipids | Terpenes | Carotenoids | Tetrapyrroles | Enzyme cofactors | Steroids | Flavonoids | Alkaloids | Polyketides | Glycosides</td></tr><tr bgcolor="pink"><td style="white-space: nowrap; width: 10%; color: pink;">Analogues of nucleic acids:</td><td align="center">The 20 Common Amino Acids ("dp" = data page)</td><td style="white-space: nowrap; width: 10%; color: pink;">Analogues of nucleic acids:</td></tr>
Alanine (dp) | Arginine (dp) | Asparagine (dp) | Aspartic acid (dp) | Cysteine (dp) | Glutamic acid (dp) | Glutamine (dp) | Glycine (dp) | Histidine (dp) | Isoleucine (dp) | Leucine (dp) | Lysine (dp) | Methionine (dp) | Phenylalanine (dp) | Proline (dp) | Serine (dp) | Threonine (dp) | Tryptophan (dp) | Tyrosine (dp) | Valine (dp)
ca:Valina

cs:Valin da:Valin de:Valineo:Valinoko:발린 hr:Valin id:Valin it:Valina he:ולין lv:Valīns lb:Valin lt:Valinas nl:Valinefi:Valiini sv:Valinuk:Валін


Linked-in.jpg