Differences between human Fe1-transferrin molecules.

Two molecular forms of Fe1-transferrin molecule can be demonstrated by anion-exchange chromatography on columns of DEAE-cellulose, pH 7.90. It is believed that co-ordination of each metal-binding site by ferric ions induces dissimilar changes in molecular conformation in the region of the binding sites which, in the case of one site, results in the molecule behaving as a weaker anion during anion-exchange chromatography. If so, this could be entirely in accord with current views that the two binding sites of transferrin do not share equal properties of iron exchange with cells. At physiological levels of transferrin iron-saturation, it is likely that two populations of Fe1-transferrin molecules form the bulk of the iron-transferrin complex.