Peptides hydrolysis/solvolysis

One possible mechanism for the hydrolysis of peptides or esters by carboxypeptidase A involves two steps with an anhydride (acyl-enzyme) intermediate.418 In the first step, the zinc(II) activates the substrate carbonyl group towards nucleophilic attack by a glutamate residue, resulting in the production of a mixed anhydride (127). Breakdown of the anhydride intermediate is rate determining with some substrates.419 An understanding of the chemistry of metal ion effects in anhydride hydrolysis is therefore of fundamental importance in regard to the mechanism of action of the enzyme. Until recently there have been few studies of metal ion-catalysed anhydride solvolysis. 

Hydrolysis (or solvolysis) of peptides and proteins involves addition of a water (or solvent) molecule across an amide bond in peptide backbones without modifying side chain structures (Fig. 2). The hydrolytic approach generates native C-terminal carboxy and N-terminal amino groups. Hence, it is particularly useful and straightforward in protein sequencing, proteomics, and protein engineering applications. 

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