Consider the malate dehydrogenase reaction from the citric acid cycle. Given the following concentrations, calculate the free energy change for this reaction at 37.0 °C (310 K). ΔG°\' for the reaction is 29.7 kJ/mol. Assume that the reaction occurs at pH 7. [malate] = 1.13 mM [oxaloacetate] = 0.270 mM [NAD ] = 390 mM [NADH] = 160 mM

Respuesta :

Answer:

[tex]\Delta G_{rxn}=23.7\ kJ/mol[/tex]

Explanation:

According to the reaction,

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

The expression for the equilibrium constant is:-

[tex]K =\frac {[oxaloacetate][NADH]}{[malate][NAD^+]}[/tex]

Given:-

[malate] = 1.13 mM

[oxaloacetate] = 0.270 mM

[tex][NAD^+][/tex] = 390 mM

[NADH] = 160 mM

Thus,

[tex]K = \frac{(0.270)(160)}{(1.13)(390)} = 0.0980[/tex]

The expression for calculation of free energy change is shown below as:-

[tex]\Delta G_{rxn}= \Delta G^0_{rxn} + 2.303RT\times log\ K[/tex]

Where, R is gas constant, 8.314 J/K.mol

T is the temperature in Kelvins

So, Given:- [tex]\Delta G^0_{rxn}=29.7\ kJ/mol[/tex]

T = 310 K

Thus,

[tex]\Delta G_{rxn}=29.7 + (2.303\times 0.008314\times 310\times log 0.0980)[/tex]

[tex]\Delta G_{rxn}=23.7\ kJ/mol[/tex]