Physical Chemistry of Protein Solutions. IX. A Light...
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GEORGESCATCHARD AND S. ZAROMB
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the corrections for the electrostatic terms in the previous columns. For the two most dilute solutions the nonelectrostatic residual is very large. This may be due partly to failure of the experimentalists to obtain the limiting slope. At 1 X and above, the residuals for the isoionic solutions are moderately constant with averages of about 700 for the Yale BM-4, 500 for their BSAI and 230 for our BMA. Our results with added acid or base are moderately consistent a t 0.15 m salt, but the electrostatic correction is much too large a t 0.003 m. The discrepancy must be in the theory and it must apply to a t least three of the four terms. It may arise from polarization of one protein molecule by the other due to shift of protons, or perhaps of chlorides, as suggested by Kirkwood and Shumaker.lg Since we are calculating here the interaction of two like charges, polarization will reduce the electrostatic effect. There are no quantitative calculations of such effects. If the ratio KIZ/
