Abstract: | The aromatic regions of the nuclear magnetic resonance spectra of horse ferricytochrome c and horse ferrocytochrome c are described. Resonance assignments have been made using NMR double-resonance techniques, spectral comparison of related proteins, the perturbing effects of extrinsic probes, and from knowledge of the X-ray structure of cytochrome c. 33 resonances arising from 39 aroumatic protons of ferrocytochrome c, and 18 resonances arising from 27 aromatic protons of ferricytochrome c have been assigned. |