Organic compounds containing amine and carboxylic groups
This article is about the class for chemicals. For the structures and properties of the standard proteinogenic amino acids, see Proteinogenic amino acid.
Structure of a generic L-alpha-amino acid in the "neutral" form needed for defining a systematic name, without implying that this form actually exists in detectable amounts either in aqueous solution or in the solid state.
Amino acids are formally named by the IUPAC-IUBMB Joint Commission on Biochemical Nomenclature in terms of the fictitious "neutral" structure shown in the illustration. For example, the systematic name of alanine is 2-aminopropanoic acid, based on the formula CH3−CH(NH2)−COOH. The Commission justified this approach as follows:
The systematic names and formulas given refer to hypothetical forms in which amino groups are unprotonated and carboxyl groups are undissociated. This convention is useful to avoid various nomenclatural problems but should not be taken to imply that these structures represent an appreciable fraction of the amino-acid molecules.
^Nelson DL, Cox MM (2005). Principles of Biochemistry (4th ed.). New York: W. H. Freeman. ISBN0-7167-4339-6.