Page 171 - Thermodynamics of Biochemical Reactions
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170 Chapter 9 Oxidation-Reduction Reactions
always positive. It is the magnitude of ArN,x that determines the slope of the plot
of E'' versus pH for a half rcaction.
Figure 9.5 shows the change in binding of hydrogen ions in five biochemical
reactions as a function of pH. The change in binding in one half-reaction may
compensate for the change in binding in the other half reaction. The change in
binding of Ht may occur in only one of the two half reactions.
These last tho plots have shown the importance of determinations of acid
dissociation constants of biochemical reactants. In the next chapter we will see
that it is also important to know the pKs of acid groups when heats of reaction
are determined calorimetrically.
