Effects of calcium ions and 2,3-diphosphoglycerate on the solubility of deoxygenated human hemoglobin

Article type: Research Article

Authors: Friederichs, E.^{a; b} | Lakomek, M.^a | Vinkler, H.^b | Tillmann, V.^c

Affiliations: [a] Department of Pediatrics, University of Göttingen, Germany | [b] Max-Planck-Insititut for Biophysical Chemistry, Germany | [c] Department of Pediatrics, Klinikum Minden, Germany

Note: [] Accepted by: Editor H. Schmid-Schn̈bein

Abstract: We have examined the influence of Ca2+-ions and 2,3-diphosphoglycerate (2,3-DPG) on the solubility of deoxygenated human hemoglobin A. We could demonstrate that Ca2+ - normally present with 0.2 µmol in the erythrocyte - reduces solubility by 13 % already in a concentration of 50 µmol. This decrease in solubility by Ca2+ could be compensated by 2,3-DPG in physiological ranges from 15–20 µmol/g hemoglobin, and there is no synergistic behaviour of these two substances. A model is presented that accounts for the intraerythrocytic Ca2+/organic phosphate equilibrium as a determining factor of deoxyhemoglobin leading to an altered deformability of erythrocytes.

Keywords: Calcium ions, 2,3-diphosphoglycerate, deoxygenated human hemoglobin

DOI: 10.3233/CH-1988-8517

Journal: Clinical Hemorheology and Microcirculation, vol. 8, no. 5, pp. 707-714, 1988