Standard apparent reduction potentials of biochemical half reactions and thermodynamic data on the species involved

Standard apparent reduction potentials Edegrees of half reactions of enzyme-catalyzed reactions are useful because they provide a global view of the apparent equilibrium constants of redox reactions. A table of Edegrees at a specified pH shows at a glance whether a given half reaction will drive another half reaction or be driven by it. This table can be used to calculate apparent equilibrium constants. Standard Gibbs energies of formation of species in a half reaction can be used to calculate Edegrees values at pHs in the range 5-9 and ionic strengths in the range of 0-0.35 M. My previously published values of Edegrees values for 42 half reactions has been extended by 22 new Edegrees values in this paper. When Delta(f)Gdegrees and Delta(f)Hdegrees are both known for all the species in an enzyme-catalyzed reaction at 298.15 K, it is possible to calculate all the standard transformed thermodynamic properties of the reaction over a range of pHs, ionic strengths, and temperatures. (C) 2004 Elsevier B.V. All rights reserved.