Separation and characterization of components of peptide libraries using on‐flow coupled HPLC—NMR spectroscopy

Abstract

AbstractThe efficiency of directly coupled HPLC—NMR spectroscopy for the separation and characterization of synthetic peptide libraries was investigated using a model system based on a mixture of all 27 tripeptide combinations of alanine (A), methionine (M) and tyrosine (Y) as the C‐terminal amides. The 1H NMR spectra were obtained in real time using on‐flow HPLC—NMR spectroscopy at 600 MHz and 21 of the 27 peptides were identified on the basis of chemical shifts and coupling constants, including the use of diagnostic values derived from 1H NMR spectra and 1H13C and 1H15N HMQC studies on authentic AAAOH and YYYOH. The effects on 1H NMR chemical shifts of pH and of varying proportions of acetonitrile and water as occurred during the gradient elution HPLC run were evaluated. The HPLC—NMR approach could provide a facile method for investigating the relative efficiency of resin‐based peptide synthesis for different amino acid combinations and should rapidly provide data suitable for deriving structure‐retention time relationships for peptides.