β-Alanine
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[edit]
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.[4] It is produced industrially by the reaction of ammonia with β-propiolactone.[5]
Sources for β-alanine includes pyrimidine catabolism of cytosine and uracil.
Athletic performance enhancement[edit]
There is evidence that β-alanine supplementation can increase exercise and cognitive performance,[13][14][15][16] for some sporting modalities,[17] and exercises within a 0.5–10 min time frame.[18] 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.[15][19]
Ingestion of β-alanine can cause paraesthesia, reported as a tingling sensation, in a dose-dependent fashion.[16] 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.[13][14] Furthermore, many studies have failed to test for the purity of the supplements used and check for the presence of banned substances.[15]
Metabolism[edit]
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.[20]
Alternatively, β-alanine can be diverted into pantothenic acid and coenzyme A biosynthesis.[20]