ABSTRACT
A major factor governing the retention behavior of peptides and proteins during reversed-phase high-performance liquid chromatography (RPC) is the relative hydrophilic/hydrophobic contribution that the side-chains of individual amino acid residues make to the overall hydrophobicity of the molecule. In fact, several research groups have determined retention coefficients for the prediction of peptide retention time in RPC on the assumption that peptide retention is primarily related to the amino acid composition of the peptide. The α-helicity of the ten peptides was determined by circular dichroism in the presence of trifluoroethanol (TFE). The helix-inducing solvent, TFE, was used to mimic the induction of α-helix in potentially α-helical peptides by the hydrophobicity of the stationary phase. Deviation of the observed retention times of the A and B series peptides from predicted retention time can be considered indicative of the effect of α-helical structure or the distribution of hydrophobic residues in the α-helical peptide on peptide retention behavior in RPC.
