NMR Study of Amino Acids and Peptides; Glycine and Valine Peptides

Abstract The PMR spectra of 22 amino acids and peptides were measured in a D2O solution. From the change in the NMR parameters in amino acids and their di- and tripeptides, it has been concluded that a tripeptide is a good model for polypeptides. The chemical shift of the α-proton of an aminoacid residue in tripeptide can be obtained from those of amino acid and dipeptide. The spin-spin coupling constant of an amino acid grows larger, and the population of a trans rotamer becomes larger, as its amino (or carboxyl) group forms a peptide bond. The PMR spectra of two diasteroisomers of valyl-valyl-valine were also measured, and the influences of the configuration of an aminoacid residue on the NMR parameters of its peptides were investigated.