Consider the malate dehydrogenase reaction from the citric acid cycle. Given the listed concentrations, calculate the free energy change for this reaction at energy change for this reaction at 37.0 ∘C (310 K). Δ????∘′ for the reaction is +29.7 kJ/mol. Assume that the reaction occurs at pH 7.[malate]=1.35 mM[oxaloacetate]=0.210 mM[NAD+]=380 mM[NADH]=150 mM

Respuesta :

Answer: The Gibbs free energy of the reaction is 22.491 kJ/mol.

Explanation:

The chemical equation for the conversion follows:

[tex]\text{Malate}+NAD^+\rightleftharpoons \text{Oxaloacetate}+NADH[/tex]

The expression for [tex]K_{eq}[/tex] of above equation is:

[tex]K_{eq}=\frac{\text{[Oxaloacetate]}\times [NaDH]}{\text{[Malate]}\times [NAD^+]}[/tex]

We are given:

[malate] = 1.35 mM

[oxaloacetate] = 0.210 mM

[NADH] = 150 mM

[tex][NAD^+]=380mM[/tex]

Putting values in above equation, we get:

[tex]K_{eq}=\frac{0.210\times 150}{1.35\times 380}=0.061[/tex]

Relation between standard Gibbs free energy and equilibrium constant follows:

[tex]\Delta G=\Delta G^o+RT\ln K_{eq}[/tex]

where,

[tex]\Delta G^o[/tex] = Standard Gibbs free energy = 29.7 kJ/mol = 29700 J/mol  (Conversion factor: 1kJ = 1000J)

R = Gas constant = [tex]8.314J/K mol[/tex]

T = temperature = [tex]37^oC=[37+273]K=310K[/tex]

[tex]K_{eq}[/tex] = equilibrium constant of the reaction = 0.061

Putting values in above equation, we get:

[tex]\Delta G=29700J/mol+(8.3145J/Kmol)\times 310K\times \ln (0.061)\\\\\Delta G=22491.05J/mol=22.491kJ/mol[/tex]

Hence, the Gibbs free energy of the reaction is 22.491 kJ/mol.