Biology Reference
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Accordingly, the colorless solutions of the amylose-grafted poly-
acetylenes in DMSO turned into violet by adding a standard iodine-
iodide solution to the polymer solutions, as the same color change in
the complex formation of amylose with iodine. The values of the
l
max
in the UV-vis spectra of the iodine complexes with the amylose graft
chains on the homopolyacetylene and copolyacetylene main chains,
and a sole amylose, were 577.0, 586.5, and 586.5 nm, respectively;
the sole amylose was prepared by the phosphorylase-catalyzed po-
lymerization of Glc-1-P using Glc
as a primer under the same con-
ditions as those for the amylose-grafted polyacetylenes. These data
indicated that the average DP of the amylose graft chains on the co-
polyacetylene was probably comparable to that of the sole amylose,
whereas the average DP of the amylose graft chains on the homopol-
yacetylene might be lower in comparison with the sole amylose. On
the basis of the aforementioned results, the following difference in
the manners during the enzymatic polymerization using the maltoo-
ligosaccharide-grafted homopolyacetylene and copolyacetylene was
assumed. The enzymatic polymerization was hardly initiated from
all the potential sites of the maltooligosaccharide primers on the
homopolyacetylene main chain due to steric hindrance, resulting in
the lower average DP. However, the less-hindered orientation of the
maltooligosaccharide primers on the copolyacetylene main chain
was probably more suitable for initiation from most of the potential
sites for the enzymatic polymerization.
To obtain the amylose-grafted polyacetylene with higher DP of the
main chain, the approach according to the polymer reaction method
was conducted (Fig. 5.4b) [28]. First, the reaction of a Glc
7
lactone
with an amine-functionalized polyacetylene with high DPs (ca. 72-
112) was performed, giving rise to a maltooligosaccharide-grafted
polyacetylene. Then, the phosphorylase-catalyzed polymerization
from the maltooligosaccharide primers on the polyacetylene
derivative was carried out to produce the desired amylose-grafted
polyacetylene with high DPs, which was explained as the synthetic
route (i)
7
(iii)
(vi) in Fig. 5.1.
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