Question

The standard free energy change in physiological conditions (G') for the reaction catalyzed by malate dehydrogenase in the citric acid cycle malate + NAD+ oxaloacetate + NADH + H+ is ~+29 kJmol-1 Calculate the actual G' at 37C if Keq' is 1.02 × 10-5

Answer 1

Answer: The actual value of $\Delta G$ is -618 J/mol

Explanation:

Relation of ree energy change and equilibrium constant

$\Delta G=\Delta G^0+2.303\times RT\times \log K_{eq}$

where,

$\Delta G$ = Free energy change

$\Delta G^o$ = standard free energy change = +29 kJ/mol =

R = universal gas constant

T = temperature = $37^0C=(37+273)K=310K$

$K_{eq}$ = equilibrium constant = $1.02\times 10^{-5}$

$\Delta G=+29000J/mol+2.303\times 8.314J/Kmol\times 310K\times \log (1.02\times 10^{-5})$

$\Delta G=29000J/mol-29619J/mol=-618J/mol$

The actual value of $\Delta G$ is -618 J/mol