8-quinolyl hydrogen glutarate

From these studies of the mode of action of carboxypeptidase A, the following two points can be extracted (a) the Zn(II) ion presumably complexes the carbonyl of ester and amide substrates, and (b) Glu-270 is also implicated as a participant, and both general-base and nucleophilic mechanisms have been proposed. There is also strong evidnece that the mechanisms are different with esters and amides. However, another mechanistic possibility to be envisaged for carboxypeptidase A is to consider a nucleophilic attack of the substrate ester or amide bond by Zn(II) coordinated hydroxide ion. Such a possibility was scrutinized by T. H. Fife and V. L. Squillacote (223). In particular, they examined the hydrolysis of the carboxyl substituted ester, 8-quinolyl hydrogen glutarate in the presence of Zn(II) ion. 

T. H. Fife and V. L. Squillacote (1978), Metal ion effects on intramolecular nucleophilic carboxyl group participation in amide and ester hydrolysis. Hydrolysis of V-(8-quinolyl)phthalamic acid and 8-quinolyl hydrogen glutarate. J. Amer. Chem. Soc. 100, 4787-4793. 

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