An overview on D-amino acids

Amino Acids. 2017 Sep;49(9):1521-1533. doi: 10.1007/s00726-017-2459-5. Epub 2017 Jul 5.


More than half a century ago researchers thought that D-amino acids had a minor function compared to L-enantiomers in biological processes. Many evidences have shown that D-amino acids are present in high concentration in microorganisms, plants, mammals and humans and fulfil specific biological functions. In the brain of mammals, D-serine (D-Ser) acts as a co-agonist of the N-methyl-D-aspartate (NMDA)-type glutamate receptors, responsible for learning, memory and behaviour. D-Ser metabolism is relevant for disorders associated with an altered function of the NMDA receptor, such as schizophrenia, ischemia, epilepsy and neurodegenerative disorders. On the other hand, D-aspartate (D-Asp) is one of the major regulators of adult neurogenesis and plays an important role in the development of endocrine function. D-Asp is present in the neuroendocrine and endocrine tissues and testes, and regulates the synthesis and secretion of hormones and spermatogenesis. Also food proteins contain D-amino acids that are naturally originated or processing-induced under conditions such as high temperatures, acid and alkali treatments and fermentation processes. The presence of D-amino acids in dairy products denotes thermal and alkaline treatments and microbial contamination. Two enzymes are involved in the metabolism of D-amino acids: amino acid racemase in the synthesis and D-amino acid oxidase in the degradation.

Keywords: Amino acid racemase; D-Asp; D-Ser; D-amino acid; D-amino acid oxidase.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Amino Acid Isomerases / chemistry*
  • Amino Acid Isomerases / metabolism
  • Amphibian Venoms / chemistry
  • Animals
  • Antimicrobial Cationic Peptides / biosynthesis
  • Antimicrobial Cationic Peptides / chemistry
  • Bacteria / chemistry
  • Bacteria / metabolism
  • D-Amino-Acid Oxidase / chemistry*
  • D-Amino-Acid Oxidase / metabolism
  • D-Aspartic Acid / chemistry*
  • D-Aspartic Acid / metabolism
  • Diet
  • Glyceraldehyde / chemistry
  • Glyceraldehyde / metabolism
  • Humans
  • Plants / chemistry
  • Plants / metabolism
  • Pyridoxal Phosphate / chemistry
  • Pyridoxal Phosphate / metabolism
  • Schiff Bases / chemistry
  • Schiff Bases / metabolism
  • Serine / chemistry*
  • Serine / metabolism
  • Stereoisomerism


  • Amphibian Venoms
  • Antimicrobial Cationic Peptides
  • Schiff Bases
  • Glyceraldehyde
  • Serine
  • D-Aspartic Acid
  • Pyridoxal Phosphate
  • D-Amino-Acid Oxidase
  • Amino Acid Isomerases