Amino acid

In chemistry, an amino acid is a molecule that contains both amine and carboxyl functional groups. In biochemistry, this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent. In the alpha amino acids, the amino and carboxylate groups are attached to the same carbon, which is called the α–carbon. The various alpha amino acids differ in which side chain (R group) is attached to their alpha carbon. They can vary in size from just a hydrogen atom in glycine, through a methyl group in alanine, to a large heterocyclic group in tryptophan.

Beyond the amino acids that recur throughout biochemistry (see below), many non-natural amino acids are also important. The chelating agents EDTA and nitriloacetic acid are alpha amino acids that are industrially synthesized (sometimes from naturally occurring amino acids).