Under standard conditions the free energy change for the hyd

Under standard conditions the free energy change for the hydrolysis of ATP is – 31 kJ/mol. What is the actual free-energy change for the reaction at 37^oC and pH 7.0, where the concentrations of ATP, ADP and P_i are 8.8 mM, 1.3 mM and 5.5 mM, respectively?

a. -49.3 kJ/mol

b. -36.4 kJ/mol

c. -25.7 kJ/mol

d. -12.7 kJ/mol

Solution

Given:-

The standard free energy of hydrolysis of ATP (G^0\')=-31kJ/mol

Temperature=37⁰C or 310.15K (273.15+37=310.15K)

pH=7

Concentration of ATP= 8.8mM

Concentration of ADP= 1.3mM

Concentration of Inorganic phosphate( Pi)= 5.5mM

The actual free energy change for the reaction is given by the following relationship:

G=-31,000kJ/mol+(8.315J/mol.K)(310.15K)In [(1.3*10^-3)(5.5*10^-3)/(8.8*10^-3)

On substituting the values in the given formula:

=-31,000+2579In (0.8125*10^-3)

=-31,000+2579(-7.11)

=-31,000+(-18,336.69)

=--31,000-18,336.69

=-49,336.69

=-49.3(kJ/mol)

so, the actual free energy change for the reaction is -49.3(kJ/mol)