Biology Reference
In-Depth Information
protective groups, and solvent systems have been developed for
the stereoselective construction of the glycosidic linkages, the
perfection in the selectivity still remains as a challenging problem
[27]. As appeared in two representative natural polysaccharides,
i.e., cellulose and starch, the importance in fashions of the glycosidic
linkages in the polysaccharides is significant for their functions
[2]. Cellulose and starch are composed of the same structural unit,
i.e., the glucose unit, but linked through the different
β
-(1
4)- and
α
4)-glycosidic linkages, respectively. Owing to the difference
in such stereochemistry of glycosidic linkages in cellulose and
starch, their roles in nature are completely different; the former is
a structural material and the latter acts as the energy source. In the
synthesis of polysaccharides, therefore, perfect control of stereo-
and regiochemistries in the glycosidic linkages is strictly demanded.
Furthermore, the chemical glycosylations require the protection-
deprotection processes of the hydroxy groups. During the multiple
reaction steps for the synthesis of polysaccharides via the chemical
glycosylations, therefore, undesired side-reactions often take place.
To develop a superior method for the synthesis of polysaccharides,
the
-(1
approach by enzymatic catalysis has been significantly
investigated [18-23]. Enzymes have several remarkable catalytic
properties compared with other types of catalyst in terms of the
stereo- and regioselectivities. In addition, enzymatic reaction is one
of the most promising basic technologies with a simple operation
under mild conditions, eliminating undesirable side-reactions.
Thus, the next chapter describes the general scope for an enzymatic
method in polysaccharide synthesis.
in vitro
References
1. Berg, J. M., Tymoczko, L. J., and Stryer, L. (2006).
, 6th
International Ed., Chapter 11 “Carbohydrates” (W. H. Freeman & Co.,
NY).
2. Schuerch, C. (1986).
Biochemistry
,
2nd Ed., eds. Mark, H. F., Bilkales, N., and Overberger, C. G., Vol. 13,
“Polysaccharides” (John Wiley & Sons, NY), pp. 87-162.
3. McMurry, J., Castellion, M. E., Ballantine, D. S., and Hoeger, C. A. (2009).
Fundamentals of General, Organic, and Biological Chemistry
Encyclopedia of Polymer Science and Engineering
, 6th Ed.
(Prentice Hall Inc., NJ).
