Magnetization‐transfer n.m.r. investigation of the hydrogen exchang in H20 of the peptide fragment B23‐B29 of insulin

Abstract
Detailed and precise information on the exchanges in water of the peptide hydrogens of the insulin fragment B23-B29 (Gly23-Phe24-Phe25-Tyr26-Thr27-Pro28-Lys29) has been obtained from magnetization-transfer measurements, and nonlinear least-squares fits of the experimental spectra using the expression for the discrete Fourier transform of a sum of exponentially damped sinusoids. From a comparison of the differential exchange rates with those expected for completely solvent-exposed peptide hydrogens, specific conformational features of the heptapeptide are suggested.