Question

1) The following equilibrium constants have been determined at 298K for these two reactions that are part of the citric acid cycle (TCA or Krebs cycle).

I AcetylCoA + oxaloacetate + H2O -->

<-- CoA + citrate

II L-malate + NAD_ox -->

<-- oxaloacetate + NAD_red

Given that K_I = 6.97 x 107 and K_II = 8.87 x 10-6, calculate the standard state transformed Gibbs free energies of reaction for each of these reactions, ∆ _rG'o .

I have gotten values of ∆ _{r I}G'o

= -4474 J/mol and ∆ _{r II}G'o = 28821 J/mol

b. For reaction II, the mitochondrial matrix has the following concentrations of components under steady state condition:

[NADox] =1.0 mM [NADred] = 0.1 mM

[malate] = 3.5 mM [oxaloacetate] = 0.0003 mM

What is the solution potential of the NADred/NADox redox couple?

I am not sure how to proceed with this. I think I need to use the equation E = E⁰ –RT/abs(v)F ln K

Are these two redox couples at or near equilibrium? Explain your answer.