(i) Plot the data and calculate the midpoint potential for a protein cofactor that was measured to have the following redox data. The parameter R is the ratio of the reduced form divided by the total

(i) Plot the data and calculate the midpoint potential for a protein cofactor that was measured to have the following redox data. The parameter R is the ratio of the reduced form divided by the total amount of protein. (ii) Propose a redox cofactor that is consistent with the data and calculated midpoint reduction potential. (iii) There are a lot of different redox cofactors with similar reduction potentials. Propose an experiment or set of experiments to further resolve what redox cofactor is being measured from the below given data.

Potential (mV)                                                     Fraction Reduced (R)

-500                                                                     0.99

-400                                                                    0.97

-300                                                                    0.90

-250                                                                   0.70

-200                                                                   0.40

-150                                                                   0.10

-100                                                                  0.02

-50                                                                   0.01

0                                                                      0.01

100                                                                 0.008

300                                                                0.005

500                                                               0.002