Page 379 - Thermodynamics of Biochemical Reactions

Chapter 11 Use of Semigrand Partition Functions

11.1 (a) Write out the semigrand partition function r ' for a system containing a weak acid and its basic form at a specified
pH. (b) Write out the equation for A, G'" of acetate at zero ionic strength. (c) Evaluate this function for af Go at pH 5 and
zero ionic strength. Use calcdGmat to confirm this value. (d) Calculate the semigrand partition function ' and use it to
calculate A, Go of acetate at pH 5.

11.2 (a) Calculate the further transformed Gibbs energies of formation of G6P, F6P, and F16BP at pH 7, I = 0, [ATP]
and
= ~W~M, [ADPI = 1G-'M at 298.15 K. (b) Calculate the further transformed Gibbs energy of formation of the
pseudoisomer group. (c) Calculate the equi1ib;ium mole fractions for G6P, F6P, and F16BP. (d) Repeat this calculation at
[ATPI = 10-2M, and [ADP] = 10-'M at 298.15 K.

11.3 (a) Print out the equation for the standard transformed Gibbs energy of formation of the pseudoisomer group consisting
of G6P, F6P, and F16BP symbolically. Assume that the system contains one mole of the pseudoisomer group. (b) Print out
the equation for the corresponding semigrand partition function r = exp[-GIRT]. (c) Calculate the amount of ATP bound by
the pseudoisomer group at [ATPJ = 0.0001 M and [ADP] = 0.01 M and then at [ATP] = 0.01 M and [ADP] = 0.01 M. (d)
Make the same calculation for the binding of ADP.

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