Biochemical thermodynamics

Abstract

Biochemists need two types of reaction equations, chemical equations in terms of species and biochemical equations in terms of reactants at specified pH and concentrations of free metal ions that are bound by reactant species. Both types of reaction equations have corresponding equilibrium constants, K for chemical reactions and K' for biochemical reactions. When the pH is specified you enter a whole new world of thermodynamics. There are new thermodynamic properties, new names (transformed thermodynamic properties), and new values, which are quite different, especially for the standard transformed Gibbs energy. This raises nomenclature problems because it is important to be able to distinguish between chemical equations and biochemical equations at a glance. It is also important to distinguish between the standard thermodynamic properties calculated from K and its temperature coefficient and the standard transformed thermodynamic properties calculated from K' and its temperature coefficient.