Effect of the substitution of light by heavy water on lysozyme KCl and NaNO3 solubility

The temperature dependence of lysozyme solubility has been measured in ligh t and heavy water in KCl and in NaNO3 at pH = 4.5. The solubilities have be en determined with the static light device previously developed to determin e the temperature dependence of lysozyme solubility in NaCl. In the present work, we show that the solubility curves in light and heavy water are shif ted by 7.2 degreesC in both KCl and NaNO3, as previously observed with NaCl . This temperature shift is the same, which is found between the temperatur e dependence of density and of other physical quantities of heavy and light water. These new results evidence a general trend of how structural aspect s of bulk water can have a profound impact on the properties of biological systems. (C) 2001 Elsevier Science B.V. All rights reserved.