Imino acid

In chemistry, an imino acid is any molecule that contains both imino (>C=NH) and carboxyl (-C(=O)-OH) functional groups.^[1]

Imino group attached to carbon

Carboxylic acid

The two functional groups that together define an imino acid

Imino acids are related to amino acids, which contain both amino (-NH₂) and carboxyl (-COOH) functional groups, differing in the bonding to the nitrogen.

The D-amino acid oxidase enzymes are able to convert amino acids into imino acids. Also the direct biosynthetic precursor to the amino acid proline is the imino acid (S)-Δ¹-pyrroline-5-carboxylate (P5C).

Related terminology

Amino acids containing a secondary amine group (the only proteinogenic amino acid of this type is proline) are sometimes named imino acids,^[2]^[3] though this usage is obsolescent.^[1]

The term imino acid is also the obsolete term for imidic acids, containing the -C(=NH)-OH group, and should not be used for them.^[1]

References

^ ^a ^b ^c IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "Imino acids". doi:10.1351/goldbook.I02959
^ Proline at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
^ http://opbs.okstate.edu/5753/Amino%20Acids.html

External links

imino+acids at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

[goldbook-1] IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "Imino acids". doi:10.1351/goldbook.I02959

[2] Proline at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

[3] ttp://opbs.okstate.edu/5753/Amino%20Acids.html

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