Page 260 - Thermodynamics of Biochemical Reactions

260 Matheinatica Solutions to Problems

3.1 Use the table of basic data to calculate the acid dissociation constants of ATP, ADP, and Pi and the equilibrium constant
for the reference reaction ATP4- + H20 = ADP3- + HP04’-+ H+ at 298.15 K and ionic strengths of 0, 05, 0.10, 0.15, 0.20,
and 0.25 M.

(BasicBiochemData2 has to be loaded)

The following program calculate the function of ionic strength that gives the standard Gibbs energy of formation of a species.

calcdGis [species-] : = Module[ {dGzero, zi, isterm},
(*This program calculates the function of ionic strength (is) that gives the
standard Gibbs energy of formation of a species at298.15 K. The input is
a list for the species that gives the standard Gibbs energy of formation,
the standard enthalpy of fonnation,the electric charge, and the number of
hydrogen atoms in the species. Energies are expressed in kJ molA-l.*)
dGzero= species[[l]];
zi= species[[3]];
/
isterrn=2.91482*(ziA2)*(isA.5) (1+1.6*isA.5);
dGzero - isterm]
The basic data on the hydrogen ion species is

hydroionsp=EO,O,l,lI

hydroion=calcdGis[hydroionspl

0.5
-2.91482 is
0.5
1 + 1.6 is

Now we need to produce a list for each species from the entries in BasicBiochemData2.

atpH0=calcdGis~atpsp~~1111
0.5
46.6371 is
-2768.1 -
0.5
1 + 1.6 is
atgHl=calCdGiS[atgSg[[2]]];

atpHZ=calcdGis [atpsp [ 131 11 ;

adpH0=calcdGis~adpsp[[llll;
adpHl=calcdGis~adpsp~[2]11;

adgH2=calcdGis[adpsp[[31]1;

ghosphateH1=calcdGis[pisp[[lllI;
phosphateH2=calcdGis[pisp[[21]1;

h2o=calcdGis lh20sp C 111 1 1 ;