LYSOZYME SOLUBILITY IN H2O AND D2O SOLUTIONS AS A FUNCTION OF SODIUM-CHLORIDE CONCENTRATION

Some spectroscopic methods require solubilization or crystallization o f proteins in heavy water because of the large difference in neutron s cattering properties between protons and deuterons. In order to quanti fy the impact of slightly different physical properties of D2O and H2O , lysozyme solubility curves have been measured for these solvents, us ing 0.2 to 3.0 M sodium chloride in 0.050 M sodium acetate buffer (pH 4.5) at 291 K. After four months of crystallization, solubility data w ere measured within 9% error and showed that the lysozyme solubility i n H2O is 1.3 times that in D2O.