2,5-Diketopiperazines (cyclic dipeptides) from glycine and L - alanine (left) and cyclodi- L -prolyl (right) formed from two L - proline molecules. The cis peptide bonds are marked blue .
Diketopiperazines (more precisely: 2,5-diketopiperazines) are cyclic peptides that are formally formed from two α- amino acids with elimination of water and form six-membered rings containing two cis -peptide bonds.
Individual evidence
↑ Hans-Dieter Jakubke and Hans Jeschkeit: Amino acids, peptides, proteins, Verlag Chemie, Weinheim (1982), ISBN 3-527-25892-2 .
