Amides nucleophile isotope effect

In a review of nucleophile isotope effects, results of studies of the hydrolysis of esters and amides by carboxypeptidase were discussed.10... 

The DjO solvent isotope effect for such a reaction should be large since proton transfer is occurring in the transition state, but the reaction is actually faster in D2O kn l ). As suggested by Bender, nucleophilic attack by the carboxylate ion on the proton-ated amide [equation (40)] may be the actual mechanism. Thus, the... 

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