Calculation of transformed thermodynamic properties of biochemical reactants at specified pH and pMg

• Published in: Biophysical chemistry 1992-07, Vol.43 (3), p.239-254
• Main Author: Alberty, Robert A.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Fundamental equation of thermodynamics; Glucose 6-phosphate; Legendre transform; Molecular biophysics; Physico-chemical properties of biomolecules; Standard transformed enthalpy of formation; Standard transformed Gibbs energy of formation
• ISSN: 0301-4622; 1873-4200
• DOI: 10.1016/0301-4622(92)85024-X

The fundamental equation of thermodynamics for the transformed Gibbs energy G′ at specified pH and pMg is used to derive the expressions for the standard transformed Gibbs energy of formation Δ f G′ i 0 of a reactant, its standard transformed enthalpy of formation Δ f H′ i 0, and its standard transformed entropy of formation Δ f S′ i 0. The standard transformed Gibbs energy of reaction Δ r G′ 0, standard transformed enthalpy of reaction Δ r H′ 0, and standard transformed entropy of reaction Δ r S′ 0 can be written as functions of pH and pMg in terms of the standard Gibbs energies of formation Δ f G i 0, standard enthalpies of formation Δ f H i 0, and standard entropies of formation Δ f S i 0 of the species involved. The expressions for Δ r G′ 0, Δ r H′ 0, and Δ r S′ 0 can be rearranged to the usual forms involving a reference reaction. The standard transformed formation properties are calculated for glucose 6-phosphate (G6P) at 298.15 K, 1 bar, pH 7, pMg 3, and I = 0.25 M.