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Consider the malate dehydrogenase reaction from the citric acid cycle. Given the

ID: 592788 • Letter: C

Question

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). G°' for the reaction is 29.7 kJ/mol. Assume that the reaction occurs at pH 7.

Consider the malate dehydrogenase reaction from the citric acid cycle. Given the following concentrations calculatethe free energy change for this reaction at 37.0 (310 K 3" for the reaction is +29.7 kJ/mol. Assume that the reaction occurs at pH 7 malate] = 1.51 mM [oxaloacetate] = 0.130 mM NAD+] = 420 mM NADH] = 170 mM Number k.J mol

Explanation / Answer

dG = DG° + RT*ln(Q)

malate + NAD+ = oxoalacetate + NADH + H+

Q = [oxoacetate][NADH][H+]/([malate][NAD+]

Q = (0.130*10^-3)(0.170)(10^-7) / ((1.51*10^-3)(0.420))

Q = 3.484*10^-9

dG = 29700 + 8.314*310 *ln( 3.484*10^-9)

dG = -20493.91

dG = -204.93 kJ/mol