title: Chemical and biochemical thermodynamics: Is it time for a reunification?
abstract: The thermodynamics of chemical reactions in which all species are explicitly considered with atoms and charge balanced is compared with the transformed thermodynamics generally used to treat biochemical reactions where atoms and charges are not balanced. The transformed thermodynamic quantities suggested by Alberty are obtained by execution of Legendre transformation of the usual thermodynamic potentials. The present analysis demonstrates that the transformed values for ΔrG'0and ΔrH'0can be obtained directly without performing Legendre transformations by simply writing the chemical reactions with all the pseudoisomers explicitly included and charges balanced. The appropriate procedures for computing the stoichiometric coefficients for the pseudoisomers are fully explained by means of an example calculation for the biochemical ATP hydrolysis reaction. It is concluded that the analysis has reunited the "two separate worlds" of conventional thermodynamics and transformed thermodynamics. In addition, it is also shown that the value of the conditional Gibbs energy of reaction, ΔrG', for a biochemical reaction is the same of the value of ΔrG for any chemical reaction involving pseudoisomers of the biochemical reagents.
authors.affiliation: Department of Pharmacy and Biotechnology, University of Bologna, I-40138 Bologna, Italy; National Institute of Biostructures and Biosystems, Italy. Electronic address: stefano.iotti@unibo.it.
authors.forename: Stefano
authors.initials: S
authors.lastname: Iotti
authors.affiliation: Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, United States.
authors.forename: Lionel
authors.initials: L
authors.lastname: Raff
authors.affiliation: Via del ponte rosso 7, 50129 Firenze, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Sabatini
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001669:Biochemical Phenomena; D001703:Biophysics / Q000379:methods; D006868:Hydrolysis; D008956:Models, Chemical; D013816:Thermodynamics
chemical_list: D000255:Adenosine Triphosphate
keywords: Balanced biochemical reaction; Biochemical thermodynamics; Conditional equilibrium constants; Legendre transforms