Fmoc-Ala-Ser(Psi(Me,Me)pro)-OH is a peptide linker featuring an Fmoc-protected N-terminal on an Ala-Ser dipeptide. The serine carboxylic acid is free to react with nucleophiles such as amines to form stable bonds, while the Fmoc group can be removed with piperidine to allow the primary amine to react such as in coupling with carboxylic acids or reductive amination with ketones or aldehydes. The serine in this structure features a contorted structure due to the presence of a hemiaminal ligating the alcohol with the amide. This dipeptide may have altered biochemical interactions due to this.
