title: Studies on the physical state of water in living cells and model systems. II. NMR relaxation times of water protons in aqueous solutions of gelatin and oxygen-containing polymers which reduce the solvency of water for NA+, sugars, and free amino acids.
abstract: This communication reports our study of the NMR relaxation times, T1 and T2 of water protons in aqueous solutions of bovine serum albumin, gelatin, polyvinylpyrrolidone, poly(ethylene oxide), and polyvinylmethylether over a wide concentration range. In contrast to solutions of gelatin and bovine serum albumin, the T1/T2 ratio of the three synthetic polymers are close to unity over the entire range studied. When combined with earlier-reported data of water made "non-solvent" to Na salts, the present data provided the basis for calculating the T1 and T2 as well as the rotational correlation time tau c of the "non-solvent" water. It was shown that only a modest increase by a factor of about 3 of tau c is enough to produce water that is "non-solvent" for Na citrate and sulfate. The new data reconciles NMR data of living cells with the theory of the cell water given in the association-induction hypothesis. The variability of tau c of "non-solvent" water also offers explanations of apparently conflicting conclusions on the physical state of cell water from dielectric measurements.
mesh_terms: D000596:Amino Acids; D002241:Carbohydrates; D002414:Cations, Monovalent; D003593:Cytoplasm / Q000502:physiology*; D005780:Gelatin; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D011108:Polymers; D012710:Serum Albumin, Bovine; D012964:Sodium; D012995:Solubility; D012996:Solutions; D014867:Water
chemical_list: D000596:Amino Acids; D002241:Carbohydrates; D002414:Cations, Monovalent; D011108:Polymers; D012996:Solutions; D014867:Water; D012710:Serum Albumin, Bovine; D005780:Gelatin; D012964:Sodium