Reduction of horse heart ferricytochrome c by glutathione: evidence for two different conformational forms of ferricytochrome c in neutral and slightly alkaline solutions.

The reduction of horse heart ferricytochrome c in neutral and slightly alkaline solutions follows biphasic kinetics. The obtained results are consistent with the existence of two conformational forms of ferricytochrome c, cyt c and cyt c¹. The conversion of cyt c to cyt c¹ occurs by deprotonation (pK～7), followed by a slow conformational change in the protein structure.