The temperature dependence of lysozyme solubility has been measured in light and heavy water in KCl and in NaNO3 at pH = 4.5. The solubilities have been determined with the static light device previously developed to determine the temperature dependence of lysozyme solubility in NaCl. In the present work, we show that the solubility curves in light and heavy water are shifted 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 temperature dependence of density and of other physical quantities of heavy and light water. These new results evidence a general trend of how structural aspects of bulk water can have a profound impact on the properties of biological systems.