Solvents for Solid-Phase Peptide Synthesis

Abstract

Effective solvation of the peptide resin is perhaps the most crucial condition for efficient chain assembly during solid-phase peptide synthesis (SPPS) (). 1H-, 2H-, 13C-, and 19F-nuclear magnetic resonance (NMR) experiments have shown that, under proper solvation conditions, the linear polystyrene chains of copoly(styrene-l%-divinylbenzene)resin (PS) are nearly as accessible to reagents as if free in solution (2–6). When PS is well solvated, diffusion of reagents is not ratelimiting (7–9). PS swelling tests are thus recommended strongly prior to synthesis (). The swelling capability of peptidyl-PS increases with increasing peptide length owing to a net decrease in free energy from solvation of the linear peptide chains (). Under proper solvent conditions, there was no decrease in synthetic efficiency of the model peptide (Leu-Ala-Gly-Val)n up to a length of 60 amino acids ().