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A dipeptide is a sometimes ambiguous designation of two classes of organic compounds: Its molecules contain either two amino acids joined by a single peptide bond or one amino acid with two peptide bonds.

Two amino acids, one peptide bond[edit]

In this usage, X dipeptide (with X designating an amino acid) must be understood as di-X peptide. This nomenclature is continued by tripeptide (three amino acids, two peptide bonds), tetrapeptide, and so on; longer chains are called oligopeptide, polypeptide, protein.


Dipeptides are produced from polypeptides by the action of the hydrolase enzyme dipeptidyl peptidase.[1] Dietary proteins are digested to dipeptides and amino acids, and the dipeptides are absorbed more rapidly than the amino acids, because their uptake involves a separate mechanism. Dipeptides activate G-cells found in the stomach to secrete gastrin.

The Bergmann azlactone peptide synthesis is a classic organic synthesis for the preparation of dipeptides.[2]


One amino acid, two peptide bonds[edit]

In this usage, X dipeptide is taken literally: One amino acid X is equipped with two minimal peptide bonds: The C terminus COOH becomes COCH3, the N terminus NH2 becomes NHCH3. For instance, alanine dipeptide is CH3CONHCH(CH3)CONHCH3.[3]


  1. ^ Steane, Richard. "Hydrolysis of a dipeptide". BioTopics. Retrieved 28 July 2014. 
  2. ^ Bergmann, M. et al., Ann. 449, 277 (1926); "Bergmann Azlactone Peptide Synthesis"
  3. ^ Head-Gordon, Teresa; Head-Gordon, Martin; Frisch, Michael J.; Brooks, Charles; Pople, John (2009). "A theoretical study of alanine dipeptide and analogs". International Journal of Quantum Chemistry. 36: 311. doi:10.1002/qua.560360725. 

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