Labile Iron Pool of Isolated Cytosol Likely Includes Fe-ATP and Fe-Citrate but not Fe-Glutathione or Aqueous Fe.

The existence of labile iron pools (LFePs) in biological systems has been recognized for decades, but their chemical composition remains uncertain. Here, the LFeP in cytosol from was investigated. Mössbauer spectra of whole vs lysed cells indicated significant degradation of iron-sulfur clusters (ISCs), even using an unusually gentle lysis procedure; this demonstrated the fragility of ISCs.