Proton NMR studies of horse ferricytochrome c. Completion of the assignment of the well resolved hyperfine shifted resonances.

1H NMR saturation transfer and nuclear Overhauser effect (NOE) measurements have been used together with two-dimensional spectra to complete the assignment of the well resolved hyperfine shifted resonances in the spectrum of horse ferricytochrome c and obtain their shifts in the reduced protein. New assignments include the beta-CH2 protons of Met-80, both ring protons of His-18, and the alpha-CH2 of Gly-29 and delta-CH2 of Pro-30, which resonate surprisingly far upfield despite the absence of any Fermi contact contribution to the shift.