“…It is known that cytochrome c can exist in at least five different conformations, 9,10 and several groups have investigated how the conformational equilibria vary with pH. 2,[19][20][21] When the pH is increased above 8, one ligand of the iron atom, Met 80 , is replaced by another ligand, lysine. This replacement changes the 'native form' of cytochrome c to the 'alkaline form' of cytochrome c. At equilibrium, a solution of cytochrome c contains a mixture of the native and alkaline forms.…”