Food Biochemistry and Food Processing

8 Enzyme Engineering and Technology 183

defined as catalytic if any of the following take
place:

1. Direct involvement in the catalytic mechanism,
   for example, as a nucleophile.


2. Exertion of an effect, which aids catalysis, on
   another residue or water molecule that is
   directly involved in the catalytic mechanism.
   3. Stabilization of a proposed transition-state
   intermediate.
   4. Exertion of an effect on a substrate or cofactor
   that aids catalysis, for example, by polarizing a
   bond that is to be broken.

Despite the impression that the enzyme’s struc-

ture is static and locked into a single conformation,

Figure 8.5.Schematic representation of the four levels of protein structure.