Nsc- and Fmoc-amino acids for automated solid-phase peptide synthesis: Comparative study of the stability in various conditions

Abstract

-2-(4-Nitrophenylsulfonyl)ethoxycarbonyl (Nsc)-amino acids have been demonstrated to be useful for solid-phase peptide synthesis [1-2]. The stability of an -protecting group in various organic media plays an important role in automated solid-phase peptide synthesis utilizing pre-dissolved amino acids. In particular, under drastic conditions a more stable group can provide better results for the synthesis of difficult sequences. We examined the stability of Nsc-amino acids under various conditions, and compared it with Fmoc-amino acids. To demonstrate its effect on peptide synthesis, we synthesized several peptides using aged Nscand Fmoc-amino acids.