Summary of Procedures to Follow the pH Studies

Let us summarize what we have said above in terms of the steps one takes to carry 

Finally, it should be noted that one can use the NMR studies to determine directly the individual group piJTa values, a method especially practical with histidines. Or one can use UV studies for groups such as tyrosine, or rates of reaction with reagents for SH groups (Fersht, 1999). 

There are five types of p Ta s which we have encountered in steady-state kinetic analyses in this chapter microscopic (or group), macroscopic (or molecular), titration, transition state, and mirage (Brockelhurst, 1996). 

Microscopic or group. The value of pKa of an individual group is of interest in connection with stmctural and mechanistic studies. Unfortunately, group p/C values cannot be measured experimentally without making assumptions, although useful estimates can sometimes be obtained (Dixon, 1976). 

Macroscopic. The macroscopic or molecular acid dissociation constants and their relationship to the group dissociation constants are defined in Section 14.2. The molecular pXg are those which are obtained experimentally (Tipton Dixon, 1979). 

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