Imino acid

Not to be confused with amino acid or Imidic acid.
1-Pyrroline-5-carboxylic acid, an N-substituted imino acid

In organic chemistry, an imino acid is any molecule that contains both imine (>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 structurally related to amino acids, which have amino group instead of imine—a difference of single vs double-bond between nitrogen and carbon. The simplest example is dehydroglycine.

D-Amino acid oxidase is an enzyme that is 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).

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