Chemistry:Β-Alanine

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β-Alanine
Skeletal formula of beta alanine
Names
IUPAC name
β-Alanine
Systematic IUPAC name
3-Aminopropanoic acid
Other names
3-Aminopropionic acid
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
EC Number
  • 203-536-5
KEGG
UNII
Properties[1][2]
C3H7NO2
Molar mass 89.093 g/mol
Appearance white bipyramidal crystals
Odor odorless
Density 1.437 g/cm3 (19 °C)
Melting point 207 °C (405 °F; 480 K) (decomposes)
54.5 g/100 mL
Solubility soluble in methanol. Insoluble in diethyl ether, acetone
log P -3.05
Acidity (pKa)
  • 3.55 (carboxyl; H2O)
Hazards
Main hazards Irritant
Safety data sheet [1]
NFPA 704 (fire diamond)
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
1
2
0
Lethal dose or concentration (LD, LC):
1000 mg/kg (rat, oral)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references
Tracking categories (test):

β-Alanine (or beta-alanine) is a naturally occurring beta amino acid, which is an amino acid in which the amino group is attached to the β-carbon (i.e. the carbon two carbon atoms away from the carboxylate group) instead of the more usual α-carbon for alanine (α-alanine). The IUPAC name for β-alanine is 3-aminopropanoic acid. Unlike its counterpart α-alanine, β-alanine has no stereocenter.

Biosynthesis and industrial route

In terms of its biosynthesis, it is formed by the degradation of dihydrouracil and carnosine. β-Alanine ethyl ester is the ethyl ester which hydrolyses within the body to form β-alanine.[3] It is produced industrially by the reaction of ammonia with β-propiolactone.[4]

Sources for β-alanine includes pyrimidine catabolism of cytosine and uracil.

Biochemical function

β-Alanine residues are rare. It is a component of the peptides carnosine and anserine and also of pantothenic acid (vitamin B5), which itself is a component of coenzyme A. β-alanine is metabolized into acetic acid.

Precursor of carnosine

β-Alanine is the rate-limiting precursor of carnosine, which is to say carnosine levels are limited by the amount of available β-alanine, not histidine.[5] Supplementation with β-alanine has been shown to increase the concentration of carnosine in muscles, decrease fatigue in athletes, and increase total muscular work done.[6][7] Simply supplementing with carnosine is not as effective as supplementing with β-alanine alone since carnosine, when taken orally, is broken down during digestion to its components, histidine and β-alanine. Hence, by weight, only about 40% of the dose is available as β-alanine.[5]

Comparison of β-alanine (right) with the more customary, chiral, α-amino acid, L-α-alanine (left)

Because β-alanine dipeptides are not incorporated into proteins, they can be stored at relatively high concentrations. Occurring at 17–25 mmol/kg (dry muscle),[8] carnosine (β-alanyl-L-histidine) is an important intramuscular buffer, constituting 10-20% of the total buffering capacity in type I and II muscle fibres. In carnosine, the pKa of the imidazolium group is 6.83, which is ideal for buffering.[9]

Receptors

Even though much weaker than glycine (and, thus, with a debated role as a physiological transmitter), β-alanine is an agonist next in activity to the cognate ligand glycine itself, for strychnine-sensitive inhibitory glycine receptors (GlyRs) (the agonist order: glycine ≫ β-alanine > taurine ≫ alanine, L-serine > proline).[10]

β-alanine has five known receptor sites, including GABA-A, GABA-C a co-agonist site (with glycine) on NMDA receptors, the aforementioned GlyR site, and blockade of GAT protein-mediated glial GABA uptake, making it a putative "small molecule neurotransmitter."[11]

Athletic performance enhancement

There is evidence that β-alanine supplementation can increase exercise and cognitive performance,[12][13][14][15] for some sporting modalities,[16] and exercises within a 0.5–10 min time frame.[17] β-alanine is converted within muscle cells into carnosine, which acts as a buffer for the lactic acid produced during high-intensity exercises, and helps delay the onset of neuromuscular fatigue.[14][18]

Ingestion of β-alanine can cause paraesthesia, reported as a tingling sensation, in a dose-dependent fashion.[15] Aside from this, no important adverse effect of β-alanine has been reported, however, there is also no information on the effects of its long-term usage or its safety in combination with other supplements, and caution on its use has been advised.[12][13] Furthermore, many studies have failed to test for the purity of the supplements used and check for the presence of banned substances.[14]

Metabolism

β-Alanine can undergo a transamination reaction with pyruvate to form malonate-semialdehyde and L-alanine. The malonate semialdehyde can then be converted into malonate via malonate-semialdehyde dehydrogenase. Malonate is then converted into malonyl-CoA and enter fatty acid biosynthesis.[19]

Alternatively, β-alanine can be diverted into pantothenic acid and coenzyme A biosynthesis.[19]

References

  1. ↑ An Encyclopedia of Chemicals, Drugs, and Biologicals (11th ed.), Merck, 1989, ISBN 091191028X , 196.
  2. ↑ Weast, Robert C., ed (1981). CRC Handbook of Chemistry and Physics (62nd ed.). Boca Raton, FL: CRC Press. p. C-83. ISBN 0-8493-0462-8. .
  3. ↑ Wright, Margaret Robson (1969). "Arrhenius parameters for the acid hydrolysis of esters in aqueous solution. Part I. Glycine ethyl ester, β-alanine ethyl ester, acetylcholine, and methylbetaine methyl ester". Journal of the Chemical Society B: Physical Organic: 707–710. doi:10.1039/J29690000707. 
  4. ↑ Miltenberger, Karlheinz (2005). "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a13_507. 
  5. ↑ 5.0 5.1 "Beta-Alanine Supplementation For Exercise Performance". http://pharmacistanswers.com/beta-alanine-supplementation-for-exercise-performance.html. 
  6. ↑ "Beta-alanine supplementation augments muscle carnosine content and attenuates fatigue during repeated isokinetic contraction bouts in trained sprinters". J Appl Physiol 103 (5): 1736–43. August 9, 2007. doi:10.1152/japplphysiol.00397.2007. PMID 17690198. 
  7. ↑ "Influence of beta-alanine supplementation on skeletal muscle carnosine concentrations and high intensity cycling capacity". Amino Acids 32 (2): 225–33. 2007. doi:10.1007/s00726-006-0364-4. PMID 16868650. 
  8. ↑ Mannion, AF; Jakeman, PM; Dunnett, M; Harris, RC; Willan, PLT (1992). "Carnosine and anserine concentrations in the quadriceps femoris muscle of healthy humans". Eur. J. Appl. Physiol 64 (1): 47–50. doi:10.1007/BF00376439. PMID 1735411. 
  9. ↑ Bate-Smith, EC (1938). "The buffering of muscle in rigor: protein, phosphate and carnosine". Journal of Physiology 92 (3): 336–343. doi:10.1113/jphysiol.1938.sp003605. PMID 16994977. 
  10. ↑ Encyclopedia of Life Sciences Amino Acid Neurotransmitters. Jeremy M Henley, 2001 John Wiley & Sons, Ltd. doi:10.1038/npg.els.0000010, Article Online Posting Date: April 19, 2001
  11. ↑ "Beta-alanine as a small molecule neurotransmitter". Neurochem Int 57 (3): 177–88. October 2010. doi:10.1016/j.neuint.2010.06.001. PMID 20540981. 
  12. ↑ 12.0 12.1 "The effects of beta-alanine supplementation on performance: a systematic review of the literature". Int J Sport Nutr Exerc Metab 24 (1): 14–27. 2014. doi:10.1123/ijsnem.2013-0007. PMID 23918656. 
  13. ↑ 13.0 13.1 "β-Alanine supplementation and military performance". Amino Acids 47 (12): 2463–74. 2015. doi:10.1007/s00726-015-2051-9. PMID 26206727. 
  14. ↑ 14.0 14.1 14.2 Hobson, R. M.; Saunders, B.; Ball, G.; Harris, R. C.; Sale, C. (9 December 2016). "Effects of β-alanine supplementation on exercise performance: a meta-analysis". Amino Acids 43 (1): 25–37. doi:10.1007/s00726-011-1200-z. ISSN 0939-4451. PMID 22270875. 
  15. ↑ 15.0 15.1 "International society of sports nutrition position stand: Beta-Alanine". J Int Soc Sports Nutr 12: 30. 2015. doi:10.1186/s12970-015-0090-y. PMID 26175657. 
  16. ↑ Brisola, Gabriel M P; Zagatto, Alessandro M (2019). "Ergogenic Effects of β-Alanine Supplementation on Different Sports Modalities: Strong Evidence or Only Incipient Findings?". The Journal of Strength and Conditioning Research 33 (1): 253–282. doi:10.1519/JSC.0000000000002925. PMID 30431532. 
  17. ↑ Bryan Saunders; Kirsty Elliott-Sale; Guilherme G Artioli1; Paul A Swinton; Eimear Dolan; Hamilton Roschel; Craig Sale; Bruno Gualano (2017). "β-alanine supplementation to improve exercise capacity and performance: a systematic review and meta-analysis FREE". British Journal of Sports Medicine 51 (8): 658–669. doi:10.1136/bjsports-2016-096396. PMID 27797728. 
  18. ↑ Guilherme Giannini Artioli; Bruno Gualano; Abbie Smith; Jeffrey Stout; Antonio Herbert Lancha Jr. (June 2010). "Role of beta-alanine supplementation on muscle carnosine and exercise performance". Med Sci Sports Exerc 42 (6): 1162–73. doi:10.1249/MSS.0b013e3181c74e38. PMID 20479615. 
  19. ↑ 19.0 19.1 "KEGG PATHWAY: beta-Alanine metabolism - Reference pathway". http://www.genome.jp/kegg-bin/show_pathway?scale=1.0&query=1.2.1.15&map=map00410&scale=&auto_image=&show_description=hide&multi_query=. 

External links



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