Mössbauer Spectroscopy of Cytochrome c

The cytochrome c of T. utilis grown in a 57-enriched medium has been investigated by Mössbauer spectrometry over a wide temperature range. The ferric cytochrome, in both lyophilized and frozen-solution form, shows magnetic hyperfine interaction at low temperatures and resembles some of the low-spin homoglobins. Spectra are in good agreement with calculations based on g values of horse-heart ferricytochrome c. The ferrous cytochrome exhibits a simple temperature-independent quadrupole splitting of 1.18 ± 0.05 mm/sec. Measurements in applied field indicate that Vzz > 0, and η ∼ 0.5.