Mitochondria have Fe(III) receptors

Recent work has provided new evidence that ATP is the major constituent of the low-M(r) iron pool in the reticulocyte. The interaction of the iron complex of ATP with mitochondria was investigated in the present experiments. When ATP-Fe³⁺ was incubated with mitochondria, Fe³⁺, free of ATP, bound with high affinity to Fe³⁺ receptors on the mitochondria. The binding was saturable and reversible. Iron which was complexed to PP(i), nitrilotriacetate, citrate, ADP and GTP also showed saturable binding to mitochondria; Fe³⁺ complexed to AMP bound non-specifically, as did Fe²⁺/ascorbate and Fe²⁺/dithionite.