400 MHz NMR Study of Isotope Effects on Albumin in H2O/D2O Solutions

Abstract: Chemical shift measurements were performed for several percentages of H2O added to D2O, in several H2O/D2O mixtures without and with a single concentration of albumin, and also in a mixture of 0.1H2O/0.9D2O containing increasing concentrations of albumin. The chemical shifts of pure mixtures decreases with increasing fraction of pure water. This is closely related to isotope effects. The chemical shift corrected for isotope effects increases with percentage of H2O. The chemical shift obtained for the mixture of 0.1H2O/0.9D2O increases with increasing concentration of albumin. These increments are consistent with fast chemical exchange in H2O/D2O mixture. In conclusion, present study reveals the presence of isotope effect on albumin in H2O/D2O solutions, and demonstrates fast chemical exchange in D2O solutions with albumin in a different way.