Alanine (Ala) also 2-aminopropanoic acid is a non-essential α-amino acid. It exists as two distinct enantiomers - L-alanine and D-alanine. L-alanine is one of the 20 amino acids most widely used in protein synthesis, second to leucine, accounting for 7.8% of the primary structure in a sample of 1,150 proteins (). D-alanine occurs in bacterial cell walls and in some peptide antibiotics.
The α-carbon atom of alanine is bound with a methyl group (-CH3), making it one of the simplest α-amino acids with respect to molecular structure and also resulting in alanine being classified as an aliphatic amino acid.
Alanine is most commonly made by transfer of an amine group to pyruvate. Because transamination reactions are readily reversible, alanine can be easily formed from pyruvate and thus has close links to metabolic pathways such as glycolysis, gluconeogenesis, and the citric acid cycle.
The methyl group of alanine is very non-reactive, and is thus rarely directly involved in protein function. However, alanine can play a role in substrate recognition or specificity, particularly in interactions with other non-reactive atoms such as carbon.
It goes through the alanine cycle to generate glucose from protein.
Any protein containing food such as meat, poultry, fish, eggs, and dairy products are rich in alanine.