ELECTROPHORETIC STUDIES ON HUMAN POLYMORPHONUCLEAR LEUKOCYTES AND ERYTHROCYTES - BINDING OF CALCIUM IONS WITHIN PERIPHERAL REGIONS

An electrophoretic analysis of calcium ion binding by human polymorphonuclear leukocytes and red blood cells indicates the presence of at least three types of anionic charge configurations in the peripheral regions of the cells. The calcium-binding sites comprise neuraminate ions, and a set of sites with a greater affinity for calcium ions than the neuraminate ions. A further set of sites with little or no affinity for calcium ions is also indicated. The electrochemical-free energies of binding for calcium ions to the surface anions indicate that the binding is relatively weak and therefore that calcium ions would be probably poor ligands for direct intercellular bridging. © 1969.