Studies on the Interaction of Metal Ions and their Hydrous Oxide Sols with Proteins. Part III. Interaction of Aluminium, Chromium, Beryllium and their Hydrous Oxide Sols with Haemoglobin

pH-metric titration of anionic haemoglobin has been carried out to ascertain the binding of AI³⁺, Cr³⁺, and Be²⁺ with the protein. From the shift in pH, when anionic protein is replaced by NaOH of the same pH, Cr³⁺ and Be²⁺  ions are assumed to be available both from the sole and the electrolytes to combine with the carboxyl groups of haemoglobin. Experiments, performed with equal volumes of the protein and electrolyte, each of pH 4.0, show decrease in pH of the protein, thereby confirming the above assumption. The combining powers are in the order Al³⁺ > Cr³⁺ > Be²⁺.