Studies on the Interaction of Metal Ions and their Hydrous Oxide Sols with Proteins. Part I. Interaction of Aluminium, Iron, and their Hydrous Oxide Sols with Gelatin

pH-metric titrations have been carried out to ascertain the binding of Al(III) and Fe(III) with the anionic gelatin. From the shift in the pH-titration curves of the metal and the alkali and those of the metal and gelatin, it is concluded that aluminium ions from the sol as well as from the electrolyte combine with the free carboxyl groups of the protein in the pH range 3-5. Viscometric studies, carried out under identical condition, support the same view. Fe(III) does not exhibit tendency of binding with the gelatin. Chloride-ion binding with gelatin is also found to be insignificant