Question

11.Calculate the standard free energy change for the oxidation of malate by NAD+ under physiological conditions. Given,  (30 points)

Malate «Oxaloacetate + 2H+ + 2e^-                 E^o’  =  0.166 V

NAD⁺+ H⁺«2e^-+ NADH                           E^o’  = - 0.315 V

Answer 1

Oxidation :

Malate ---------> oxaloacetate + 2 H+ + 2e-         Eo = 0.166 V

Reduction :

NAD+ +   H+ + 2e-   ----------> NADH              Eo = - 0.315 V

Eocell = Eored - Eooxid

         = - 0.315 - 0.166

         = - 0.481 V

delta Go = - n F Eocell

              = - 2 x 96485 x - 0.481 x 10^-3

delta Go = 92.8 kJ/mol