For example, the tripeptide glutathione is synthesized in two steps from free amino acids, by two enzymes: glutamate–cysteine ligase (forms an isopeptide bond, which is not a peptide bond) and ...

In conclusion, we would like to emphasize two points: first, the importance of the cis conformation of peptide bonds in protein structures, especially if it is a Xaa–nonPro peptide bond ...