[eagerinsight]

Why are the Gibbs energies for the hydrolysis of Mg++ATP and H4ATP less negative than the deprotonated form of of ATP (ATP4-). I think the differences in Gibbs are due to differences in entropy more than enthalpy? Do the electrostatic repulsions of ATP4- increase or decrease entropy?

I also considered that for H4ATP the terminal phosphate group would be a good leaving group, thus increasing disorder (more stuff) and increasing entropy, with enthalpy becoming less negative? Mg++ complexes with the negatively charged oxygen on the gamma and beta phosphate groups (diminishing repulsion), isn't this how some enzymes decrease the energy needed to hydrolyze ATP, forming the products easier, more stuff, more entropy, then enthalpy would have to get less negitive?

[Yggdrasil]

Why are the Gibbs energies for the hydrolysis of Mg++ATP and H4ATP less negative than the deprotonated form of of ATP (ATP4-). I think the differences in Gibbs are due to differences in entropy more than enthalpy? Do the electrostatic repulsions of ATP4- increase or decrease entropy?

I think enthalpy is the more important factor to consider here.

I also considered that for H4ATP the terminal phosphate group would be a good leaving group, thus increasing disorder (more stuff) and increasing entropy, with enthalpy becoming less negative? Mg++ complexes with the negatively charged oxygen on the gamma and beta phosphate groups (diminishing repulsion), isn't this how some enzymes decrease the energy needed to hydrolyze ATP, forming the products easier, more stuff, more entropy, then enthalpy would have to get less negitive?

Consider H₂PO₄^- v PO₄^3-.  Based on the number of resonance structures, which would you expect to be the better leaving group?