The thermochemical characterization of sodium dithionite, flavin mononucleotide, flavin-adenine dinucleotide and methyl and benzyl viologens as low-potential reductants for biological systems

[摘要]

The heat of reaction (ΔH) of Fe(CN)₆³⁻, Methyl Viologen, FMN and FAD with S₂O₄²⁻ in aqueous buffer solutions was measured calorimetrically. In addition ΔH values for reduction of Fe(CN)63-, FMN and FAD by reduced Methyl Viologen were determined. The resulting calorimetric data and corresponding E₀^′ values were combined to yield thermodynamic data for these simple reducing agents in a form useful for applications to biological reactions. Thermodynamic data for the reduction of spinach ferredoxin are also presented.