MOBILITY OF WATER IN BIOLOGICAL-SYSTEMS STUDIED BY O-17 NMR VIA MULTIPLE-QUANTUM FILTERED RELAXATION ANALYSIS

Multiple-quantum filtering NMR sequences were used to study the multie xponential relaxation behaviour of (H2O)-O-17 in the presence of macro molecules. By this means, the fraction and the correlation time of wat er in slow motion, or 'bound' water, were determined, in addition to t he relaxation time of bulk water in the extreme narrowing limit, Exper iments were carried out on aqueous solutions of bovine serum albumin, hen egg white lysozyme and intact human red blood cells in which intra cellular water properties were studied, The small fraction of bound wa ter of less than 1% seems to correspond to 'strongly bound' water, whe reas the behaviour of bulk water was different from that of pure water and may be due to weak (or transient) interactions with macromolecule s. The experiments and the data analysis gave reproducible results whi ch support the idea that diverse samples could be studied in this way in order to help understand their water properties. (C) 1997 John Wile y & Sons, Ltd.