Iron mobilization from ferritin by chelating agents

Area of Science:

• Biochemistry
• Metalloprotein Chemistry
• Pharmacology

Background:

• Ferritin is the primary intracellular iron storage protein.
• Understanding iron release mechanisms is crucial for managing iron overload disorders.
• Chelating agents are investigated for their potential in mobilizing stored iron.

Purpose of the Study:

• To investigate the in vitro efficacy of various chelating agents in releasing iron from horse spleen ferritin.
• To explore the influence of flavin mononucleotide (FMN) and other agents on iron mobilization.
• To evaluate the impact of ferritin preparation methods on iron release.

Main Methods:

• In vitro study of iron release from horse spleen ferritin using chelators: desferrioxamine B, rhodotorulic acid, 2,3-dihydroxybenzoate, 2,2'-bipyridyl, and pyridine-2-aldehyde-2-pyridyl hydrazone (Paphy).
• Comparison of iron release from ferritin prepared by classical thermal denaturation versus a modified procedure.
• Assessment of the effects of FMN, ascorbate, EDTA, citrate, and oxalate on chelator-mediated iron release.

Main Results:

• Desferrioxamine B and rhodotorulic acid were the most effective iron-releasing agents from both ferritin preparations.
• Ferritin prepared without thermal denaturation released iron more effectively.
• FMN blocked iron release by certain chelators but simulated it with others (bipyridyl, Paphy). Ascorbate and EDTA also modulated iron release significantly.

Conclusions:

• Chelator efficacy in iron release varies, influenced by ferritin preparation and the presence of co-factors like FMN and ascorbate.
• Bipyridyl can complex ferrous iron (FeII) after reduction by FMN, unlike desferrioxamine B.
• These findings provide insights into storage iron mobilization relevant to iron overload treatment strategies.