Carboxypeptidases definition

The exact disposition of the side chains in a globular protein is difficult to define in solution. Although it is likely that the peptide main chain (backbone) of the protein is relatively rigid, the side chains have been shown to be undergoing motion of several different types (see lysozyme, peroxidase, and carboxypeptidase). This means that the full definition of atomic positions in the structure requires a knowledge of the time dependence of their coordinates. The motion of side chains is likely to be different in the crystal and solution states, but this difference may well... 

A second form of acid—base catalysis reflects another, more general definition of acids and bases. In the Lewis formulation, an acid is an electron-pair acceptor, and a base is an electron-pair donor. Metal ions, including such biologically important ones as Mn +, Mg +, and Zn, are Lewis acids. Thus, they can play a role in metal-ion catalysis (also called Lewis acid-base catalysis). The involvement of Zn + in the enzymatic activity of carboxypeptidase A is an example of this type of behavior. This enzyme catalyzes the hydrolysis of... 

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