Amino Acids Modification

Chemical modifications of peptides introduced strategically at potential enzymatic cleavage sites may dramatically increase the in vivo stability of peptide drug candidates. One simple approach to stabilizing a peptide is to modify the side-chains of some of the amino acids involved in the protease recognition site. The residues of interest are replaced by natural or non-natural amino acids with chemically similar side-chains. The introduction of non-natural amino acids generates modifications in the secondary and tertiary structures of a peptide, and is used to further enhance the stability and activity of peptide sequences.

Functions of unusual & non-natural amino acids modification

Enhance selectivity
Improve receptor binding
Modify bioactivity to target (agonists and antagonists)
Increase in vivo half-life
Enhance transportion through cell membranes