The advantages of transition state and group acid dissociation constants for pH-dependent enzyme kinetics

Abstract

A simple equilibrium analogy is presented as an aid to appreciate the concept of transition state dissociation constants in enzymatic reactions. Reactions are discussed in detail from the standpoint of transition state, ground state, group and molecular ionization constants. For n acid groups there are n ! possible reaction schemes. It is shown that the n ! number of reaction schemes can be predicted by the use of both transition state and group acid dissociation constants, whereas by use of the molecular ionization constants, only one of the n ! possibilities is obtained.