Exploring Chemical Modifications of Aromatic Amino Acid Residues in Peptides

Abstract The chemical diversification of biomolecules set forth a significant area of research that constitutes an important intersection between chemistry and biology. Amino acids and peptides are the fundamental building blocks of proteins and play essential roles in all living organisms. While significant efforts have been geared toward the chemical modification of amino acid residues, particularly the functionalization of reactive functional groups such as lysine NH2 and cysteine SH, the exploration of the aromatic amino acid residues of tryptophan, tyrosine, phenylalanine, and histidine has been relatively limited. Therefore, this review highlights strategies for the side-chain functionalization of these four aromatic amino acids in peptides, with a focus on elucidating the underlying mechanisms. We have also illustrated the use of these modifications in the chemical and biological realm. 1 Introduction 2 Tryptophan Modifications 3 Tyrosine Modifications 4 Phenylalanine Modifications 5 Histidine Modifications 6 Perspectives and Future Outlook