title: Carboxypeptidase A mechanisms.
abstract: The mode of binding of a ketonic substrate, which is an analogue of esters in which the O of the scissile bond is replaced by CH2, to carboxypeptidase A is similar to that of Gly-Tyr. The site is S'1, with the side chain in the pocket of the enzyme, the carboxylate salt-linked to Arg-145, and the carbonyl group bound to Zn. Thus, esters are probably cleaved at the peptide cleavage site, although not necessarily with the same rate-controlling step or by the same detailed mechanism. The large differences found between the behavior of the enzyme in solution and in one crystalline phase do not apply to a different crystalline phase.
mesh_terms: D001665:Binding Sites; D002268:Carboxypeptidases / Q000378:metabolism*; D004952:Esters / Q000378:metabolism; D007700:Kinetics; D010455:Peptides / Q000378:metabolism; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D013696:Temperature; D013820:Thermolysin / Q000378:metabolism
chemical_list: D004952:Esters; D010455:Peptides; D002268:Carboxypeptidases; D013820:Thermolysin