Page 220 - Thermodynamics of Biochemical Reactions

220 Matheniatica Solutions to Problems

This program can be used to calculate standard transformed Gibbs energies of reaction or standard transformed enthalpies of
reaction in kJ mol-l. To calculate the changes in standard transformed enthalpy, an h is appended to the name of the
reactant.

dGrxatp = calctrGerx[atp+h20 +de == adp+pi, {S, 6, 7, 8, 9}, 0.251
{-32.5633, -33.2166, -36.0353, -41.0742, -46.7021)

dHrxatp=calctrGerx[atph+h2oh+de==adph+pih, {S, 6, 7, 8, 9}, 0.251
{-26.386, -25.6892, -23.0327, -21.558, -21.3455}

The corresponding standard transformed entropies of reaction are given by

dHrxatp-dGrxatp
0.29815
{20.7188, 25.2473, 43.611, 65.4575, 85.0466)

where these values are in J K-' mol-I . The standard transformed entropy of reaction increases rapidly above pB 7 because
of the production of hydrogen ions. There is an increase in the standard transformed entropy because of the increase in the
number of species in the reaction.

This program can also be used to produce plots of standard transformed properties of reaction versus pH or ionic strength.

AG' i/ (kJ/mol)
-36- -34h

-36
-38.
-40.
-42.
-44-

9.3 Calculation of apparent equilibrium constants

calckprime[eg, pHlist-, islist-] := Module[{energy, dG),(*Calculates the apparent
equilibrium constant at specified pHs and ionic strengths for a biochemical reaction
typed in the form atp+hao+de==adp+pi. The names of reactants call the appropriate
functions of pH and ionic strength. pHlist and is list can be lists.*)
energy = Solve [eq, de] ;
dG = energy[[l,l,2]] /. pH -> pHlist /. is -> islist;
EA(-(dG/(8.31451*0.29815)))l
calckprime[atp+h2o+de== adp+gi, 15, 6, 7, 8, 9}, 0.251
6 7 8
{506774., 659585., 2.05626 10 , 1.5698 10 , 1.51989 10 ]