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Updated: May 25, 2026

Setup of Capillary Electrophoresis-Inductively Coupled Plasma Mass Spectrometry (CE-ICP-MS) for Quantification of Iron Redox Species (Fe(II), Fe(III))
Published on: May 4, 2020
Spectroscopic characterization of (57)Fe-enriched cytochrome c
Bogdan M Leu1, Tom H Ching, Cuong Tran
1Department of Physics and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA 02115, USA. leu@aps.anl.gov
Researchers developed a milder method to replace iron in heme proteins with iron-57 for spectroscopy. This ensures protein integrity, validating its use as a model for native proteins.
Area of Science:
- Biophysical Chemistry
- Biochemistry
- Spectroscopy
Background:
- Heme iron dynamics in proteins like cytochrome c are crucial for function.
- Mössbauer spectroscopy and nuclear resonance vibrational spectroscopy require isotopic enrichment (57Fe).
- Traditional demetallization methods use harsh acids, potentially damaging the protein.
Purpose of the Study:
- To develop and validate a safer demetallization method for heme iron replacement.
- To confirm the structural integrity of (57)Fe-reconstituted cytochrome c.
- To establish the utility of metal-substituted heme c proteins as reliable models.
Main Methods:
- Demetallization using ferrous sulfate-hydrochloric acid (safer) and hydrofluoric acid (harsher).
- Reconstitution of cytochrome c with (57)Fe.
- Confirmation of structural integrity via absorption spectra and resonance Raman spectroscopy.
Main Results:
- The ferrous sulfate-hydrochloric acid method effectively demetallizes heme iron.
- (57)Fe-reconstituted cytochrome c maintains structural integrity in both oxidation states.
- Resonance Raman spectra confirm the preservation of protein structure.
Conclusions:
- A milder, safer demetallization method is effective for preparing (57)Fe-labeled heme proteins.
- (57)Fe-substituted cytochrome c serves as a reliable model for studying native proteins.
- This work facilitates advanced spectroscopic investigations of heme protein dynamics.
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