Transferrin

an iron-binding protein able to carry two ferric iron ions (Fe3+)

Description
Transferrin loaded with iron is recognized by transferrin receptors on cell surfaces, taken up in a vesicle, and following acidification of the vesicle and release of the iron inside the cell is recycled to the extracellular space. As transferrin is the predominant iron-binding protein, the medical laboratory test of the total iron-binding capacity (TIBC) of blood, assessing the degree to which iron-binding sites can be saturated, is an indirect measure of blood transferrin.