Chemistry Reference
In-Depth Information
In other techniques, the protein may be bound by some copolymer of maleic anhydride, where the
anhydride groups react with some available amine groups on the enzyme [
42
]. Other techniques may
utilize cyanuric chloride attached to polysaccharides for immobilization [
42
]:
O
O
Cl
enzyme
N
N
N
N
N
N
+
OH
Cl
N
Cl
N
N
R
R
R
enzyme
NH
Polyaminostyrene can be diazotized or treated with thiophosgene and then used in enzyme
immobilization [
43
]:
n
n
n
S
CCl
2
HNO
2
N
N
NH
2
S
N
H
enzyme
H
enzyme
n
n
H
N
N
N
enzyme
enzyme
H
N
S
Because epoxy groups on carrier molecules are capable of reacting with an amine or a carboxylic
acid groups of the enzymes, they can be used in enzyme immobilization. A variation on the technique
is to react a vinyl monomer that contains an epoxy groups, like glycidyl methacrylate or glycidyl
acrylate, with the enzyme first. The product is then polymerized or copolymerized through the vinyl
portion [
44
]. As stated earlier, in many cases, immobilization of enzymes is accompanied by some
loss of activity. In some instance, the loss in activity can be severe. A special technique, however, was
developed [
45
], where the enzyme called protease is immobilized on a polymer with amino glucose
units to form covalently bonded carbohydrate-protein conjugates. In aqueous solution, the conjugated
enzymes show about the same catalytic activity as native enzymes. At elevated temperatures,
however, they exhibit enhanced stability. In addition, they are capable of catalyzing reactions in
organic solvents that denature and inactivate the native enzymes [
45
].
