In response to the query of Ing-Nang Wang on equilibrium constants, I
suggest some recent articles by Robert A. Alberty. Ther most recent, I
believe is "Levels of thermodynamic treatment of biochemical reaction
systems" in the Biophysical J. 65:1243-1254 (1993). There are many useful
references therein, one of which is pertinent to the reactions you are
interested in. This "Standard thermodynamic formation properties for the
Adenosine 5'-triphosphate series" is by Alberty and Goldberg in Biochemistry
31:10610-10615. I hope this is what you are looking for.
Richard W. Hendler