Food Biochemistry and Food Processing

8 Enzyme Engineering and Technology 209

enzymes to insoluble supports, due to their wide-
spread surface exposure and high reactivity, espe-
cially in slightly alkaline solutions.
It is important that the amino acids essential to the
catalytic activity of the enzyme are not involved in
the covalent linkage to the support (Dravis et al.
2001). This may be difficult to achieve, and en-
zymes immobilized in this fashion generally lose

activity upon immobilization. This problem may be

prevented if the enzyme is immobilized in the pres-

ence of saturating concentrations of substrate, prod-

uct, or a competitive inhibitor to protect active site

residues. This ensures that the active site remains

“unreacted” during the covalent coupling and re-

duces the occurrence of binding in unproductive con-

formations.

Figure 8.20.Representation of the methods by which an enzyme may be immobilized: (A) adsorption, (B) covalent
coupling, (C) cross-linking, (D) matrix entrapment, and (E) encapsulation.