Standard transformed Gibbs energy table

Table 4.1 Standard Transformed Gibbs Energies in kJ mol 1 of Hydrolysis of ATP as a Function of Temperature, pH, and Ionic Strength...

Table 6.2 Standard Transformed Gibbs Energies of Formation at 298.15 K, pH 7, and 0.25 M Ionic Strength, Standard Further Transformed Gibbs Energies of Formation at [ATP] = 10 4 M and [ADP] = 10 2 M, and Standard Further Transformed Gibbs Energies of Formation at [ATP] = 10 2 M and [ADP] = 10-2 M...

A number of biochemical reactions involve proteins as reactants, and so it is important to be able to determine the standard transformed Gibbs energies of formation of their reactive sites at specified pH. The standard transformed Gibbs energies of formation of the active sites of ferredoxin, cytochrome c, and thioredoxin are given in tables discussed earlier in Chapter 4. 

In order to calculate the standard transformed Gibbs energies of formation of the four oxygenated forms of hemoglobin, we need the value of AfG° for molecular oxygen in aqueous solution at 21.5°C. The NBS Table (1992) indicates that ArG0(O2(ao)) = 16.1 kJ mol-1 at 21.5°C. The value of ArG 0(T(O2)) is calculated using... 

Table 7.1 Standard Transformed Gibbs Energy of Formation AfG ° and Standard Further Transformed Gibbs Energies of Formation AfG ° of Hemoglobin Tetramer at 21.5JC, 1 bar, pH 7.4, [Cl ] = 0.2 M, and 0.2 M Ionic Strength...

The fundamental equations for the dimer are similar to those for the tetramer. Table 7.3 gives AfG"° and AtG"°(TotD) at the same three oxygen concentrations as Table 7.1. The standard transformed Gibbs energies of formation of the three forms of the dimer are based on the convention that AfG °(T) = 0. 

Table 7.5 Standard Transformed Gibbs Energies of Formation for the Catalytic Site of Fumarase in kJ moF1 at 25 C and Ionic Strength 0.01 M...

The values of A, G ° for the catalytic site, succinate, and site-succinate calculated in this way are shown in Table 7.5. Similar calculations have been made for D-tartrate, L-tartrate, and meso-tartrate using data from Table 7.4. Since the ArG° values for these three reactants are not known, the convention has been adopted that they are equal to zero. Table 7.5 shows that standard transformed Gibbs energies of formation at specified pH values can be calculated for an unoccupied binding site and the binding site occupied by a ligand. 

Since tables of standard apparent reduction potentials and standard transformed Gibbs energies of formation contain the same basic information, there is a question as to whether this chapter is really needed. However, the consideration of standard apparent reduction potentials provides a more global view of the driving forces in redox reactions. There are two contributions to the apparent equilibrium constant for a biochemical redox reaction, namely the standard apparent reduction potentials of the two half-reactions. Therefore it is of interest to compare the standard apparent reduction potentials of various half reactions. 

Table 9.3 Standard Transformed Gibbs Energies (in kJ moE ) of Reactions and Standard Apparent Reduction Potentials (in volts) at 289.15 K, 1 bar, pH 7, and Ionic Strength 0.25 M for Reactions Involved in the Methane Monooxygenase Reaction...

Table 1 Standard Transformed Gibbs Energies of Formation in kJ mol- at 298.15 K, pH 7, and Ionic Strengths of 0, 0.10, and 0.25 M...

Table 2 Standard Transformed Gibbs Energies of Formation of Reactants at 298.15 K, Ionic Strength 0.25 M, and pHs of 5, 6, 7, 8, and 9...

These tables have been given to 0.01 kJ mol-1. In general this overemphasizes the accuracy with which these formation properties are known. However for some reactants for which species are in classical tables, this accuracy is warranted. An error of 0.01 kJ mol-1 in the standard transformed Gibbs energy of a reaction at 298 K corresponds with an error of about 1 % in the value of the apparent equilibrium constant. It is important to understand that the large number of digits in these tables is required because the thermodynamic information is in differences between entries. 

Table 3.1 Standard transformed Gibbs energies of formation in kJ mol of inorganic phosphate at 298.15 K.

The function phosGT can be used to construct the following table of the standard transformed Gibbs energies of formation of inorganic phosphate. 

The biochemical reactants ATP, ADP, and phosphate each exist in several different ionized and metal bound forms. For example, ATP is an equilibrium mixture of the species ATP, HATP, H ATP, MgATP ", MgHATP", Mg ATP". Additional species would also have to be considered if Ca + were present. Thus, ATP has often been denoted in the literature as ZATP or as (ATP). When it is clear that one is dealing with total amounts of substances, it is not necessary to use either the Z or tot. Thus, these designations are not used in this table. In the above equation, c° = 1 mol dm" it is included to make K dimensionless. The standard transformed Gibbs energy of reaction A G ° at specified conditions of temperature T, pressure P, ionic strength 1, pH, and pMg can be calculated from 1C ... 

Values of A G ° and K can rdso be calculated for many biochemical reactions by using the table Standard Transformed Gibbs Energies of formation for Biochemical Reactants in Section 7 of this Handbook. 

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