L-alanine is the L-enantiomer of alanine. It has a role as an EC 4.3. 1.15 (diaminopropionate ammonia-lyase) inhibitor and a fundamental metabolite. Alanine, or α-alanine, is an α-amino acid that is used in the biosynthesis of proteins. It contains an amine group and a carboxylic acid group, both attached to the central carbon atom which also carries a methyl group side chain. Consequently it is classified as a nonpolar, aliphatic α-amino acid.