The Effect of Iodination on the Binding of Haptene to Arsonic Antibody

Summary The effect of iodination on the binding capacity of purified antiphenylarsonic acid antibody was studied by means of the equilibrium dialysis technique. A direct correlation was found between the uptake of iodine and the loss in binding capacity. Since the presence of homologous haptene protected the binding sites from destruction by iodination, evidence was obtained that iodine reacts directly with groups at the active site. Furthermore, a comparison of the experimentally determined losses in binding capacity with the probable losses calculated from the assumption of one or two reactive groups at each site indicated that only one iodine reactive group is present at each site.