Biology Reference
In-Depth Information
6.4 Chemoenzymatic Synthesis of Amylose-
Grated Anionic Polysaccharides
The water-soluble anionic polysaccharides such as alginic acid and
xanthan gum are representative hydrocolloids, which are used as a
stabilizer, a viscous agent, and a structure provider in food industries.
To develop the functional hydrocolloids, the chemoenzymatic method
was extended to alginic acid as an anionic polysaccharide [13] to give
the amylose-grafted alginate (Fig. 6.7) [14]. Alginic acid is a linear
polysaccharide composed of (1
→
4)-linked
β
-
d
-mannuronate and
(1
-
l
α-l-guluronate units. For this approach, an amine-
functionalized maltooligosaccharide was chemically introduced into
sodium alginate by condensation with carboxylates of the alginate
to produce a maltooligosaccharide-grafted alginate. Then, the
phosphorylase-catalyzed enzymatic polymerization of Glc-1-P from
the maltooligosaccharide primers on the alginate main chain was
conducted to produce the amylose-grafted alginate.
→
4)-linked
α
OH
OH
O
OH
O
OH
HO
HO
O
OH
HO
HO
OH
OH
O
H
2
N
O
OH
+
OH
N
3
HO
OH
O
O
HO
5
OH
O
OH
O
HO
HO
O
5
O
OH
HN
OH
NaBH
4
OOC
HO
N
3
O
OOC
O
O
OH
OH
HO
O
O
OH
n
OH
OH
R
H
O
R
O
O
HO
HO
O
OH
OH
O
EDAC / NHS
O
OH
OH
HO
HO
O
O
n
5
OH
Glc-1-P
Phosphorylase
HO
OH
O
O
OH
OH
O
HN
HO
HO
OH
R =
COO
or
O
OH
HO
OH
OH
O
R
H
O
R
O
NH
2
5
O
OH
OH
O
HO
HO
O
O
n
HN
OH
O
OH
OH
O
HO
HO
NH
COO
OH
R =
or
O
OH
O
HO
OH
O
m
OH
HO
O
HN
NH
O
Figure 6.7
Chemoenzymatic synthesis of amylose-grafted alginate by
means of phosphorylase-catalyzed enzymatic polymerization.
