Factors affecting iron and transferrin release from rabbit reticulocyte ghosts to cytosol

Erythrocyte haemolysate interacts with ATP–Fe to form a complex containing iron, ATP and 13 800 MW polypeptide

“…The iron was, instead, shunted out of the low MW ATP-Fe pool to a high MW complex. A similar high MW complex is formed when reticulocytes are pulsed with 53Fe-labelled transferrin (Blackburn & Morgan, 1977;Nunezet al, 1980;Pollack & Campana, 1981; Egyed, 1983).…”

Role of Heme and Iron Metabolism in Controlling Protein Synthesis

“…The 59Fe was found in ferritin suggesting that this molecule is the intermediate in intracellular iron transport 77–79 . However, transferrin also has been suggested as the intercellular iron carrier after its release from the endocytotic vesicles using this same approach 79,80 . Thus, this method does not clearly show which, if either, of these molecules is involved in intracellular iron transport.…”

“…Label appeared in ferritin, hemoglobin, and a protein of 5000 molecular weight which could reversibly bind iron. In both of these approaches only very small amounts of iron in its intermediary state have been found, 77–81 suggesting a very rapid turnover. From all of the above it appears that the natural cytoplasmic donor of iron for the mitochondrion remains as yet unknown.…”

Receptor‐mediated iron uptake and intracellular iron transport

“…The properties of ATP-Fe may explain, in part, the existence of a pool of iron in the cell that is not in a low-MW form and that is not iron incorporated into any of the usual iron-binding molecules. This pool is seen when reticulocytes are pulsed with "Fe-labeled transferrin as '"Fe "loosely bound" to hemoglobin (i.e., although not incorporated into heme, coeluting with hemoglobin from a molecular sieve column) [44][45][46]. Iron is shunted to this "loosely bound" complex [47] when reticulocytes-with their heme synthesis blocked by succinylacetone-take up iron.…”