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β-Alanine

Names
IUPAC name 3-Aminopropanoic acid
Other names β-Alanine 3-Aminopropionic acid
Identifiers
CAS Number	107-95-9
3D model (JSmol)	Interactive image
ChEBI	CHEBI:16958
ChEMBL	ChEMBL297569
ChemSpider	234
DrugBank	DB03107
ECHA InfoCard	100.003.215
IUPHAR/BPS	2365
KEGG	D07561
PubChem CID	239
UNII	11P2JDE17B
CompTox Dashboard (EPA)	DTXSID0030823
InChI InChI=1S/C3H7NO2/c4-2-1-3(5)6/h1-2,4H2,(H,5,6)Key: UCMIRNVEIXFBKS-UHFFFAOYSA-N InChI=1/C3H7NO2/c4-2-1-3(5)6/h1-2,4H2,(H,5,6)Key: UCMIRNVEIXFBKS-UHFFFAOYAL
SMILES O=C(O)CCN
Properties
Chemical formula	C3H7NO2
Molar mass	89.093 g/mol
Appearance	Bipyramidal crystals
Density	1.437 g/cm (19 °C)
Melting point	207 °C decomp.
Solubility in water	soluble
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Y verify (what is  ?) Infobox references

β-Alanine (or beta-alanine) is a naturally occurring beta amino acid, which are amino acids in which the amino group is at the β-position from the carboxylate group (i.e., two atoms away, see Figure 1). The IUPAC name for β-alanine would be 3-aminopropanoic acid. Unlike its normal counterpart, α-alanine, β-alanine has no chiral center.

β-Alanine is not used in the biosynthesis of any major proteins or enzymes. It is formed in vivo by the degradation of dihydrouracil and carnosine. It is a component of the naturally occurring peptides carnosine and anserine and also of pantothenic acid (vitamin B₅) which itself is a component of coenzyme A. Under normal conditions, β-alanine is metabolized into acetic acid.

β-Alanine is the rate-limiting precursor of carnosine, which is to say carnosine levels are limited by the amount of available β-alanine. 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.

Typically studies have used supplementing strategies of multiple doses of 400 mg or 800 mg, administered at regular intervals for up to eight hours, over periods ranging from 4 to 10 weeks. After a 10 week supplementing strategy, the reported increase in intramuscular carnosine content was an average of 80.1% (range 18 to 205%).

L-Histidine, with a pKa of 6.1 is a relatively weak buffer over the physiological intramuscular pH range. However, when bound to other amino acids this increases nearer to 6.8-7.0. In particular, when bound to β-alanine the pKa value is 6.83, making this a very efficient intramuscular buffer. Furthermore, because of the position of the beta amino group, β-alanine dipeptides are not incorporated proteins and thus can be stored at relatively high concentrations (millimolar). Occurring at 17-25 mmol/kg (dry muscle), 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.

β-Alanine, provided in solution or as powder in gelatine capsules, however, causes paraesthesia when ingested in amounts above 10 mg per kg body weight (bwt). This is variable between individuals. Symptoms may be experienced by some individuals as mild even at 10 mg per kg bwt, in a majority as significant at 20 mg per kg bwt, and severe at 40 mg per kg bwt. However, an equivalent amount (equimolar) to 40 mg per kg bwt, ingested in the form of histidine containing dipeptides in chicken broth extract, did not cause paraesthesia.

It is probable that the paraesthesia, a form of neuropathic pain, results from high peak blood-plasma concentrations of β-alanine since greater quantities, ingested in the form of the β-alanine / histidine (or methylhistidine) containing dipeptides (i.e. carnosine and anserine) in meat, do not cause the same symptoms. In this case the β-alanine absorption profile is flattened but sustained for a longer period of time, whereas, the β-alanine samples in the studies were administered as gelatine capsules containing powder. This resulted in plasma concentrations rising rapidly, peaking within 30 to 45 minutes, and being eliminated after 90 to 120 minutes. The paraesthesia caused is no indication of efficacy since the published studies undertaken so far have utilised doses of 400 mg or 800 mg at a time to avoid the paraesthesia. Furthermore, excretion of β-alanine in urine accounted for 0.60%(+/-0.09), 1.50%(+/-0.40) and 3.64%(+/-0.47) of the administered doses of 10, 20, or 40 mg per kg body weight, indicating greater losses occurring with increasing dosage.

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 ligant glycine itself, for strychnine-sensitive inhibitory glycine receptors (GlyRs) (the agonist order: glycine >> β-alanine > taurine >> alanine, L-serine > proline).

A high potency artificial sweetener, called suosan, is derived from beta-alanine.

References

1. The Merck Index: 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, Florida: CRC Press. p. C-83. ISBN 0-8493-0462-8..
3. Derave W, Ozdemir MS, Harris R, Pottier A, Reyngoudt H, Koppo K, Wise JA, Achten E. (August 9, 2007). "Beta-alanine supplementation augments muscle carnosine content and attenuates fatigue during repeated isokinetic contraction bouts in trained sprinters". J Appl Physiol. 103 (5): 1736. doi:10.1152/japplphysiol.00397.2007. PMID 17690198.{{cite journal}}: CS1 maint: multiple names: authors list (link)
4. ^ Hill CA, Harris RC, Kim HJ, Harris BD, Sale C, Boobis LH, Kim CK, Wise JA. (2007). "Influence of beta-alanine supplementation on skeletal muscle carnosine concentrations and high intensity cycling capacity". Amino Acids. 32 (2): 225–33. doi:10.1007/s00726-006-0364-4. PMID 16868650.{{cite journal}}: CS1 maint: multiple names: authors list (link)
5. ^ Harris, RC; Tallon, MJ; Dunnett, M; Boobis, L; Coakley, J; Kim, HJ; Fallowfield, JL; Hill, CA; Sale, C; et al. (2006). "The absorption of orally supplied β-alanine and its effect on muscle carnosine synthesis in human vastus lateralis". Amino Acids. 30 (3): 279–289. doi:10.1007/s00726-006-0299-9. PMID 16554972. {{cite journal}}: Explicit use of et al. in: |first9= (help)
6. Bate-Smith, EC (1938). "The buffering of muscle in rigor: protein, phosphate and carnosine". Journal of Physiology. 92 (3): 336–343. PMC 1395289. PMID 16994977.
7. 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: 47–50. doi:10.1007/BF00376439.
8. 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
9. Template:ChemID

External links

• KEGG map of β-alanine metabolism
• International Society of Sports Nutrition Conference Proceedings

• Amino acids