ROLE OF IRON IN REACTION BETWEEN RABBIT TRANSFERRIN AND RETICULOCYTES

The effect of the degree of iron saturation of transferrin on the kinetics of the interaction with reticulocytes was studied using pure rabbit transferrin and rabbit reticulocytes. The increase in the association rate constant measured with iron-saturated transferrin compared with iron-free transferrin was not statistically significant. The dissociation rate constant for the reaction between reticulocytes and transferrin which was low in iron content was larger than that for iron-saturated transferrin. More iron-containing than iron-free transferrin was bound to the reticulocytes at equilibrium. This difference was largely due to the iron-containing molecules having a longer mean residence time on the reticulocyte. The efficiency of the iron transfer process was 86%, indicating that a proportion of the iron-containing transferrin molecules taken up by reticulocytes was refluxed without donating all their iron to the cells. © 1969, American Chemical Society. All rights reserved.