Proton magnetic relaxation mechanisms and solution dynamics of L-histidine

Longitudinal and transverse proton relaxation rates have been measured for L-histidine in water solution. From a comparison of the former, measured in the selective and non-selective modes, it was found that the dipolar relaxation mechanism dominates the proton relaxation process. Molecular and internal motions have been quantified on the basis of a ‘jump’ relaxation model. Complex relaxation behaviour has been observed for protons of the histidyl species.