Physiological iron chelators pyrophosphate and citrate have different effects on the proportions of monoferric transferrin metalloforms.

Human serum transferrin can bind up to two iron atoms, one in each of its two domains which are known as the N-lobe and the C-lobe. Ferric pyrophosphate and ferric citrate have been shown to direct loading into the C-lobe and N-lobe, respectively. We report that the iron supplement ferric pyrophosphate citrate directs iron to the C-lobe. We also show that pyrophosphate directs iron to the C-lobe as a free anion even at the concentrations found in human plasma. This indicates that pyrophosphate may play a physiological role in transferrin iron loading and body iron homeostasis. We also present a validation of an existing micellar capillary electrophoresis technique for separating the four transferrin metalloforms, which has potential to be adapted for use in a clinical setting.
Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests. Richard K. Watt reports equipment, drugs, or supplies was provided by Rockwell Medical Inc. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024. Published by Elsevier Inc.)