Molecular aspects of the binding of absorbed iron to transferrin

Abstract

To study the molecular aspects of the binding of absorbed Fe to plasma transferrin, 59Fe with high specific activity was administered via intragastric tube to Fe-deficient rabbits. The distribution of the absorbed 59Fe among the molecular forms of Fe-transferrin was analyzed using urea-polyacrylamide gel electrophoresis. Absorbed Fe was bound to circulating transferrin 1 atom at a time. In 4 of 5 animals, absorbed Fe was predominantly bound to the site in the N-terminal domain of the protein. Thus, the 2 sites of transferrin may differ in their ability to load absorbed Fe.