Question

4. A biochemist carries out an enzymatic activity assay of alcohol dehydrogenase at 37°C using 200 uM NADH and an excess of substrate and allows the reaction to proceed to equilibrium. At equilibrium, the concentration of NADH is measured to be 1.1 x 10–8 uM while the concentration of NAD+ is calculated to be 200 uM. What is the biochemical free energy change (deltaG'o) of the reaction system for converting NADH to NAD+, in kJ/mol? (R=8.314J/mol*K)

Answer 1

T = 37 0C = (37 +273.15 ) K = 310.15 K

At equilibrium,

Concentration of NADH , [NADH] = 1.1*10-8 uM

Concentration of NAD+, [NAD+] = 200 uM

Equilibrium constant,

Plugging in values,

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Free energy change is given by:

Plugging in values,