Organic compounds containing amine and carboxylic groups
This article is about the class of chemicals. For the structures and properties of the standard proteinogenic amino acids, see Proteinogenic amino acid.
Structure of a typical L-alpha-amino acid in the "neutral" form
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups.[1] Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins.[2] Only these 22 appear in the genetic code of life.[3][4]
Amino acids can be classified according to the locations of the core structural functional groups (alpha- (α-), beta- (β-), gamma- (γ-) amino acids, etc.), other categories relate to polarity, ionization, and side chain group type (aliphatic, acyclic, aromatic, polar, etc.). In the form of proteins, amino acid residues form the second-largest component (water being the largest) of human muscles and other tissues.[5] Beyond their role as residues in proteins, amino acids participate in a number of processes such as neurotransmitter transport and biosynthesis. It is thought that they played a key role in enabling life on Earth and its emergence.
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:[6]
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. ISBN 0-7167-4339-6.
^Richard Cammack, ed. (2009). "Newsletter 2009". Biochemical Nomenclature Committee of IUPAC and NC-IUBMB. Pyrrolysine. Archived from the original on 12 September 2017. Retrieved 16 April 2012.
^Rother, Michael; Krzycki, Joseph A. (1 January 2010). "Selenocysteine, Pyrrolysine, and the Unique Energy Metabolism of Methanogenic Archaea". Archaea. 2010: 1–14. doi:10.1155/2010/453642. ISSN 1472-3646. PMC 2933860. PMID 20847933.
^Latham MC (1997). "Chapter 8. Body composition, the functions of food, metabolism and energy". Human nutrition in the developing world. Food and Nutrition Series – No. 29. Rome: Food and Agriculture Organization of the United Nations. Archived from the original on 8 October 2012. Retrieved 9 September 2012.
^"Nomenclature and Symbolism for Amino Acids and Peptides". IUPAC-IUB Joint Commission on Biochemical Nomenclature. 1983. Archived from the original on 9 October 2008. Retrieved 17 November 2008.
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/ˈɡlaɪsiːn/ ) is an aminoacid that has a single hydrogen atom as its side chain. It is the simplest stable aminoacid (carbamic acid is unstable). In the...
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digestibility-corrected aminoacid score (PDCAAS) is a method of evaluating the quality of a protein based on both the aminoacid requirements of humans...
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properties of a specific aminoacid. In glycine, the simplest aminoacid, the R group is a hydrogen atom, but in all other aminoacids it is contains one or...
arrangement of atoms in an aminoacid-chain molecule. Proteins are polymers – specifically polypeptides – formed from sequences of aminoacids, which are the monomers...
The Strecker aminoacid synthesis, also known simply as the Strecker synthesis, is a method for the synthesis of aminoacids by the reaction of an aldehyde...
is an essential aminoacid that is used in the biosynthesis of proteins. Leucine is an α-aminoacid, meaning it contains an α-amino group (which is in...
aerobic respiration. In addition, the cycle provides precursors of certain aminoacids, as well as the reducing agent NADH, that are used in numerous other...
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