NMR measurements of proton exchange between solvent and peptides and proteins

Scope and limitations of the NMR based methods, equilibration and magnetiza tion transfer, for measuring proton exchange rates of amide protons in pept ides and proteins with water protons are discussed. Equilibration is applie d to very slow processes detected by hydrogen-deuterium exchange after a so lute is dissolved in D2O. Magnetization transfer allows to study moderately rapid processes in H2O. A number of precautions should be undertaken in or der to avoid systemic errors inherent in the magnetization transfer method.