Conformations of side chains of somatostatin very high field proton NMR studies

The high field proton NMR spectra (500 and 600 MHz) of the peptide hormone somatostatin in D₂O are reported. The results obtained are used to derive values of the couplings and chemical shifts related to the solution conformation of several of the side chains. This work resolves a discrepancy in the literature concerning the assignments of resonances in the spectrum. It also provides a means of testing the accuracy of obtaining values for these couplings and shifts in previous 2D NMR studies at lower field from strongly coupled multiplets in spectra of this complexity.