Studies of Light Scattering by Hemoglobin Molecules under the Effect of Iron (III) Chloride and Various pH Levels

Abstract

A lot of literature sources discuss diseases associated with the hemoglobin protein [1, 2]. In the modern world, more than 800 million people suffer from anemia [3]. Assessing the level of hemoglobin in the circulatory system is one of the ways to diagnose anemia. Hemoglobin protein is also a promising source of bioactive peptides [4]. The aim of the work was to identify the reasons leading to conformation changes of this protein. It still remains unclear what exactly causes disruption of its functionality. Human hemoglobin from Sigma H7379 was studied in the work; all experiments were conducted on a dynamic light scattering spectrometer—Photocor Complex. Experimental data were obtained using optical methods of static and dynamic light scattering. The work included an analysis of the behaviour of hemoglobin protein molecules in aqueous and aqueous-saline solutions with changes in solution parameters (pH, addition of iron chloride III). At values of pH \(<(3.56\pm 0.15)\) and pH \(>(10.4\pm 0.2)\), the hemoglobin molecule underwent conformational changes, resulting in the disintegration of the quaternary structure into \(\alpha\beta\)-dimers and individual \(\alpha\)- and \(\beta\)-globules. As a result of the study, it was found that the addition of FeCl\({}_{3}\) to aqueous solutions of hemoglobin increases the size and mass of scattering particles, which can be explained by the adsorption of Fe\({}^{3+}\) ions on the protein surface. However, upon reaching a certain concentration of FeCl\({}_{3}\), the pH of the solution was lowered to such an extent that it caused conformational changes in hemoglobin, leading to the disintegration of its quaternary structure. These results can be taken into account when creating medicinal drugs for the treatment of anemia and other diseases associated with the hemoglobin protein.