Dynamic Characteristics of the Octahedral Jahn–Teller Copper Cu2+ Complex and the Octahedral Iron Fe3+ Complex in Ceruloplasmin. Electron Paramagnetic Resonance Method

The electron paramagnetic resonance (EPR) spectra of copper Cu2+ and iron Fe3+ ions in ceruloplasmin were studied in a wide temperature range. The copper Cu2+ ion was shown to be Jahn–Teller active. The EPR spectra of magnetic iron Fe3+ ions consist of lines with g = 2.06 ± 0.01 and g = 4.33 ± 0.01. The dynamic characteristics of the octahedral Jahn–Teller copper complex (the height of the potential barrier of the crystal field in the nearest environment of copper E0 = 9.16 × 10–4 eV) and the octahedral iron complex (E0 = 9.89 × 10–4 eV) were determined from the temperature dependences of the intensities of EPR lines.