Two Different Sites Amino Acids

Note that k and are the intrinsic binding constants on a and b, respectively k and kj are the conditional intrinsic binding constants, i.e.. 

Clearly, from the experimental values of and one caimot obtain the three independent intrinsic constants and k =kjc/k.  

The traditional approximation made to solve for the instrinsic constants is to assume that the effect of the (unionized) carboxylic group on the dissociation of the NHj group is not much changed upon esterification of the carboxyl group. If we denote by the binding (or association) constant to the NHj group of the esterified amino acid, then the approximation 

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