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valine

 
Dictionary: val·ine   (văl'ēn', vā'lēn') pronunciation
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n.
An essential amino acid, C5H11NO2.

[VAL(ERIC ACID) + -INE2.]


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Britannica Concise Encyclopedia: valine
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One of the essential amino acids, found in most proteins. Produced industrially by hydrolysis of proteins or by chemical synthesis, it is used in biochemical and nutritional research and as a dietary supplement.

For more information on valine, visit Britannica.com.

Food and Nutrition: valine
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An essential amino acid, rarely, if ever, limiting in foods, one of the branched-chain amino acids.

Food and Fitness: valine
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An essential amino acid found in all proteins. It is one of three branched-chain amino acids. It is seldom deficient in the diet.

Dental Dictionary: valine
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(val′ēn)
n

One of the essential amino acids. See also amino acid.

Sports Science and Medicine: valine
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Home > Library > Health > Sports Science and Medicine

An essential amino acid found in grains (e.g. corn) and legumes (e.g. beans).

 
Columbia Encyclopedia: valine
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valine (văl'ēn), organic compound, one of the 22 α-amino acids commonly found in animal proteins. Only the L-stereoisomer appears in mammalian protein. It is one of several essential amino acids needed in the diet, as the human body cannot synthesize it from simpler metabolites. Young adults need about 23 mg of this amino acid per day per kilogram (10 mg per lb) of body weight. Valine can be degraded into simpler compounds by the enzymes of the body; an inherited defect in one of the enzymes involved in this process results in a rare disorder called maple syrup urine disease. Valine contributes to the structure of proteins into which it has been incorporated by the tendency of its side chain to participate in hydrophobic interactions. The structure of valine was established in 1906, after it had been first isolated from albumin in 1879. See isoleucine.

Veterinary Dictionary: valine
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Val; a naturally occurring amino acid.

Wikipedia: Valine
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Valine
L-valine-skeletal.svg
L-valine-3D-sticks.png
IUPAC name
Other names 2-amino-3-methylbutanoic acid
Identifiers
CAS number 516-06-3 Yes check.svgY,
72-18-4 (L-isomer)
640-68-6 (D-isomer)
PubChem 1182
EC-number 208-220-0
SMILES
Properties[1]
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
 Yes check.svgY (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.

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

  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[4]

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

References

  1. ^ 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 .
  2. ^ "Nomenclature and symbolism for amino acids and peptides (IUPAC-IUB Recommendations 1983)", Pure Appl. Chem. 56 (5): 595–624, 1984, doi:10.1351/pac198456050595 .
  3. ^ 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 .
  4. ^ 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

v • d • e
The 20 Common Amino Acids ("dp" = data page)
Branched-chain amino acids
Isoleucine (dp) · Leucine (dp) · Valine (dp)
Non Branch-chain
Alanine (dp) · Arginine (dp) · Asparagine (dp) · Aspartic acid (dp) · Cysteine (dp) · Glutamic acid (dp) · Glutamine (dp) · Glycine (dp) · Histidine (dp) · Lysine (dp) · Methionine (dp) · Phenylalanine (dp) · Proline (dp) · Serine (dp) · Threonine (dp) · Tryptophan (dp) · Tyrosine (dp)
Other classifications
Major families of biochemicals
Saccharides/Carbohydrates/Glycosides · Amino acids/Peptides/Proteins/Glycoproteins · Lipids/Terpenes/Steroids/Carotenoids · Alkaloids/Nucleobases/Nucleic acids · Cofactors/Phenylpropanoids/Polyketides/Tetrapyrroles
v • d • e
Amino acid metabolism metabolic intermediates
K→acetyl-CoA
G
other
valine→
Other
see also enzymes, disorders


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Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.  Read more
Britannica Concise Encyclopedia. Britannica Concise Encyclopedia. © 2006 Encyclopædia Britannica, Inc. All rights reserved.  Read more
Food and Nutrition. A Dictionary of Food and Nutrition. Copyright © 1995, 2003, 2005 by A. E. Bender and D. A. Bender. All rights reserved.  Read more
Food and Fitness. Food and Fitness: A Dictionary of Diet and Exercise. Copyright © 1997, 2003 by Oxford University Press. All rights reserved.  Read more
Dental Dictionary. Mosby's Dental Dictionary. Copyright © 2004 by Elsevier, Inc. All rights reserved.  Read more
Sports Science and Medicine. The Oxford Dictionary of Sports Science & Medicine. Copyright © Michael Kent 1998, 2006, 2007. All rights reserved.  Read more
Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/.  Read more
Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved.  Read more
Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Valine".  Read more