Free energy change table

In all these phosphate-releasing reactions, the several resonance forms available to Pi (Fig. 13-1) stabilize this product relative to the reactant, contributing to an already negative free-energy change. Table 13-6 lists the standard free energies of hydrolysis for a number of phosphorylated compounds. 

Even this set of equations represents an approximation, because ATP, ADP, and Pi all exist in solutions as a mixture of ionic species. This problem is discussed in a later section. For now, it is enough to note that the free energy changes listed in Table 3.3 are the group transfer potentials observed for transfers to water. 

Hexokinase catalyzes the phosphorylation of glucose from ATP, yielding glncose-6-P and ADR Using the values of Table 3.3, calculate the standard-state free energy change and equilibrium constant for the hexokinase reaction. 

FIGURE 7.11. Calculated and observed free-energy changes for the Asn-155— Thr, the Asn-155—>Leu, and the Asn-155— Ala mutations. The calculated and observed free energies are compared in the table in the upper part of the figure. 

Table 3 Free energy changes in the ionic dissociation of carbon-carbon cr bonds in some hydrocarbons at 25°C. ...

Fig. 10. Relationship between (AC i,2 —0.5 ACJi.i) and the standard free energy change (AG ij) of the redox reactions at 25 °C. Open circles, Ce(IV) + Fe(phen)3 reactions in 0.50 Af HjS04. Closed circles, Fe + +Fe(phen)3 reactions in 0.50 M HCIO4. Numbers refer to complexes in Table 32. (From Dulz and Satin, by courtesy of The American Chemical Society.)...

Table 3-1. Calculated potential and free energy differences for path B (in kcal/mol) between the determined structure and the reactant (ES complex), where Ait is the total HF potential energy difference, A Eqm refers to the QM energy difference between two QM subsystems. A 1 qm/MM is the free energy change in the QM/MM interaction, and A F = AEqm + A I qm/MM- Numbers without parentheses correspond to the present work and numbers in parentheses correspond to our previous determinations (path D) [33]...

Table 1 Equilibrium constants and free energy changes for hole transport...

Experimental determinations undertaken prior to the discovery of electrospray as a source of ions have shown86 87 that the bond strength of H-bonded complexes XH —A" increases with the gas-phase acidity of XH and the gas-phase basicity of A-. This relation has been examined82 for the special case where A- were a variety of anions produced by electrospray and XH = OH2, on the basis of the hydration energy data (see Table 8) and gas-phase basicities AGj A-) = AG°cid (AH) corresponding to the free energy change for the gas-phase reaction ... 

The gas-phase lifetime of N20- is 10-3 s in alkaline solutions, it is still >10-8 s. Under suitable conditions, N20- may react with solutes, including N20. The hydrated electron reacts very quickly with NO (see Table 6.6). The rate is about three times that of diffusion control, suggesting some faster process such as tunneling. NO has an electron affinity in the gas phase enhanced upon solvation. The free energy change of the reaction NO + eh (NO-)aq is estimated to be --50 Kcal/mole. Both N02- and N03- react with eh at a nearly diffusion-controlled rate. The intermediate product in the first reaction, N02-, generates NO and... 

Hence the experimental equilibrium constants of Table IV are proportional to the constants for ionization into ion pairs, and the ratios of the if exp reflect differences in the tendency of different molecules to form ion pairs. Since standard free energies are proportional to the logarithms of equilibrium constants, differences in the tabulated free energies represent differences in the standard free energy change for ionization, even though the individual values represent the standard free energy for the overall process of ionization plus dissociation. 

The individual free energy components show the relative contributions from the electrostatic and the van der Waals interactions. The free energy change for the annihilation of the charges on the ligand in the complex and in solution is almost identical within the limits of the estimation. However, the van der Waals free energy component for the complex is more than that of the isolated ligand (Table 1). 

Table 1. Dependence of free energies (kcal/mol) on the residue-based cutoff radii Rc (A) for generation of cation-solvent (c-s) and solvent-solvent (s-s) interaction lists. Free energy changes are given for the forward AGf (i.e. 8-methyl-N5-deazapterin — 8-methyl-pterin) and reverse AGr mutations of the electrostatic terms. ...

Table 3. Free energy changes (kcal/mol) calculated for the mutation 6,8-dimethyl-N5-deazapterin — 6-methyl-N5-deazapterin in solution. Results for 80 ps simulation, with 200 ps...

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