Physicochemical properties of structured water in human albumin and gammaglobulin solutions

The physicochemical properties of the different phases of water molecules w ere studied in concentrated solutions (132 g/L) of human serum albumin and gammaglobulin by H-1 NMR relaxometry. Spin-lattice (T1) relaxation times of total water and structured water (non-freezable water) were measured at 40 MHz above and below the freezing point of bulk water (ordinary, liquid wat er) at different temperatures. Analysis of the temperature dependence of th e T1 demonstrated that total water differed qualitatively while structured water characteristics changed both quantitatively and qualitatively in the two protein solutions. Comparison of the temperature dependence of the stru ctured water's Tl in the two solutions in the presence of an increasing con centration of manganese chloride allowed two main conclusions to be drawn. Firstly, the differences observed in total water and structured water physi cochemical properties are directly related to protein structure and three-d imensional arrangement. Secondly, the motion of structured water determines the motion of the total water in the system through the values of the tran slational diffusion and chemical exchange correlation times tau (D) and tau m. (C) 2001 Societe francaise de biochimie et biologie moleculaire / Editio ns scientifiques et medicales Elsevier SAS. All rights reserved.