Biology Reference
In-Depth Information
OH
HO
HO
OH
O
O
OH
OH
O
O
HO
HO
HO
OH
O
HO
OH
O
OH
O
O
5
OH
OH
HO
n
O
O
R
HN
O
OH
O
R
EDC / NHS
O
O
O
HO
AcO
OH
CH
3
OH
Water
+
HO
NH
2
OH
COO
R
=
OH
OH
N
or
OH
O
O
HO
O
O
HO
EDC=
HO
OH
N
C
N
OH
OH
O
O
n
-
OOC
O
O
O
HO
HO
OH
Glc-1-P
Phosphorylase
OH
O
HO
-
OOC
OH
O
OH
O
O
O
O
HO
5
AcO
NHS =
HO
N
OH
HO
H
3
C
OH
O
O
HO
OH
HN
O
Xanthan gum
NH
C
OH
OH
O
O
O
HO
O
O
OH
OH
n
R'
O
OH
O
OH
O
R'
O
O
O
HO
AcO
HO
HO
OH
OH
CH
3
OH
O
O
O
HO
OH
R'
=
COO
or
HO
OH
HO
HO
OH
O
OH
O
m
HO
O
HN
NH
C
O
Figure 6.8
Chemoenzymatic synthesis of amylose-grafted xanthan gum by
means of phosphorylase-catalyzed enzymatic polymerization.
testing, the fracture strain values increased with increasing the
functionalities or DPs of the amylose graft chains, whereas the fracture
stress values were mostly unchanged regardless of the functionalities
or DPs. It can be considered that the Fe
3+
-treated hydrogels of the
amylose-grafted xanthan gums are constructed by not only the
ionically cross-linking with Fe
3+
and the double-helix conformation
of xanthan gum chains but also the double helix conformation of
amylose graft chains, because amylose is also known to readily form
the double-helix conformation. The presence of the double-helix
structure between amylose graft chains probably contributed to the
formation of looser network structure in the hydrogels, resulting in
the enhancement of the fracture stress values.
6.5 Chemoenzymatic Synthesis of Amylose-
Grated Polypeptide
Glycoproteins, peptidoglycans, and proteoglycans are saccharide-
polypeptide conjugates, which occur in blood, plasma membranes,
intercellular matrixes, and connective tissues. These naturally
occurring
saccharide-polypeptide
conjugates
play
important
