Studying chemical shift of water in protein and enzyme solutions with D2O by 400MHz NMR

NMR T?(spin-lattice) and T?(spin-spin) relaxation times in protein and enzyme solutions have been studied since 1960?s. Many approackes have been used for explaining the relaxation mechanisms. One of them is the chemical exchange of protons between free water and water bound te solids.In this study, chemical shifts of the D2O solutions, to which sucrose, maltose, pepsin and BSA were added, were studied versus concentration fo added substancer. Chemical shifts of materials were disadaly changed by concentration. They have a negative or positive slope to a certain concentration. Then the slope bicomes suddenly reversed. For this reason. There is no reqularly linear dependence on the concentration and in turn There is no fast chemical Exchange between free and bound phoses.