It has become increasingly clear in recent years that some proteins are capable of binding most common anions, and many studies with organic dye anions, detergent anions, and with some inorganic anions have been reported. On the basis of some of these studies Klotz and Urquhart4 have suggested that a "binding index" exists, which can be computed from the amino acid composition of a protein, and which will predict the relative affinity of different proteins for any anion. It would be desirable to test this hypothesis for chloride ion, since this is the most abundant anion in physiological systems. Unfortunately, chloride binding has been measured for only one protein, human serum albumin. The results obtained with this protein were, however, especially interesting in that they showed that an indirect method of computing chloride binding from the effect of chlorides upon the pH of an isoionic protein solution gives results in good agreement with direct determination. Since data on pH changes resulting from salt addition are available in the literature for a few proteins, it becomes possible to compute the extent of chloride binding for these proteins, and this has been done in this paper for egg albumin, beta lactoglobulin, and horse carboxyhemoglobin.
Proceedings of the Iowa Academy of Science
© Copyright 1950 by the Iowa Academy of Science, Inc.
"Interaction Between Proteins and Chloride Ion,"
Proceedings of the Iowa Academy of Science, 57(1), 225-233.
Available at: https://scholarworks.uni.edu/pias/vol57/iss1/25