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Ferrous ion release from ferritin by ultraviolet-A radiations
M Aubailly1, R Santus, S Salmon
1Muséum National d'Histoire Naturelle, Laboratoire de Physico-Chimie de l'Adaptation Biologique, (INSERM U.312), Paris, France.
Photochemistry and Photobiology
|November 1, 1991
Summary
UV-A irradiation of ferritin releases iron (Fe2+). This photoreduction process, dependent on wavelength but not pH or oxygen initially, suggests a role for electron transfer from hydroxyl ligands, potentially impacting skin photobiology.
Area of Science:
- Biochemistry
- Photochemistry
- Biophysics
Background:
- Ferritin is the primary protein responsible for iron storage in the Fe(III) state.
- Iron homeostasis is crucial for cellular function, and ferritin plays a key role in regulating intracellular iron levels.
Purpose of the Study:
- To investigate the effect of UV-A irradiation on iron release from ferritin.
- To elucidate the mechanism of iron photoreduction and its dependence on environmental factors.
- To assess the potential implications of this phenomenon in skin photobiology.
Main Methods:
- UV-A irradiation of horse spleen ferritin loaded with Fe(III).
- Spectrophotometric quantification of released Fe2+.
- Wavelength dependence, pH, oxygen, and formate ion effects were analyzed.
Main Results:
- UV-A irradiation induced Fe2+ release from ferritin.
- Initial iron release quantum yield was wavelength-dependent but independent of pH and oxygen.
- Fe2+ release plateau was significantly influenced by pH and oxygen levels.
- Formate ions enhanced Fe2+ production, indicating an electron transfer mechanism.
Conclusions:
- UV-A irradiation triggers a photoreduction of ferritin, leading to Fe2+ release.
- The process involves electron transfer from hydroxyl ligands, suggesting a novel photoreduction pathway.
- The findings highlight a potential mechanism relevant to iron metabolism and skin photobiology under UV exposure.