Chitin enzymatic synthesis

The polymerization of 1 mentioned above should be compared with the enzymatic synthesis of chitin reported by Kobayashi and coworkers, in which an oxazoline derivative of A, A -diacetylchitobiose, the repeating unit of chitin was polymerized in the presence of chitinase enzyme via ring-opening addition process to give an artihcial chitin (Scheme 6) [5]. The method using an enzyme, however, may not enable synthesis of nonnatural-type aminopolysaccharide because the reaction catalyzed by chitinase enzyme is limited to the formation of (1 4)-P-glycosidic linkage. 

Sakamoto J, Kobayashi S. Enzymatic synthesis of 3-0-Methylated chitin oligomers from new derivatives of a chitobiose oxazoline. Chem. Lett. 2004 33 698-699. 

Makino A., Ohmae M., Kobayashi S., Enzymatic synthesis of cellulose, chitin and chitosan, Bio Industry, 22, 2005, 12-21. 

Akiyama, K., Kawazu, K., and Kobayashi, A. 1995. A novel method for chemo-enzymatic synthesis of elicitor-active chitosan oligomers and partially Af-acetylated chitin ohgomers using M-acetylated chitotrioses as substrate in a lysozyme-catalyzed transglycosylation reaction system. Carbohydr. Res. 279 151-160. 

Tokuyasu, K., Ono, H., Hayashi, K., and Mori, Y. 1999. Reverse hydrolysis reaction of chitin deacetylase and enzymatic synthesis of P-D-GlcNAc-(l-4)-GlcN from chitobiose. Carbohydr Res 322 26-31. 

Figure 8. Enzymatic synthesis of chitin using Bacillus sp. chitinase with the oxazoline derivative of chitobiose as donor. 

Fujioka, M., Okada, H., Kusaka, Y, Nishiyama, S Noguchi, H., Ishii, S., and Yoshida, Y. [2004). Enzymatic Synthesis of Chitin- and Chitosan-graft-Aiiphatic Poiyesters, Macromol. Rapid Commun., 25,1776-1780. 

We have achieved the synthesis of structurally well-defined natural and unnatural oligo- and polysaccharides via enzymatic polymerization utilizing natural glycosyl hydrolases as catalysts (26-57) cellulose and xylan prepared by cellulase (52-54), an amylose oligomer by amylase (55), chitin by chitinase (56, 57), altematingly 6-(9-methylated cellulose by cellulase (55), and a cellulose-... 

According to the advantages mentioned above, enzyme-catalyzed polymer syntheses are also of increasing interest. Typical examples of enzymatically produced macromolecules are the synthesis of polysaccharides and polyesters using hydrolases, the production of biopolymers like cellulose, xylan, chitin, or hgnin by hydrolases or peroxidases, and the synthesis of polyaromatic... 

For the polysaccharide synthesis, enzymatic polymerization has been developed as a new in vitro synthesis method of natural and unnatural polysaccharides having complicated structures.The method utilizes a hydrolysis enzyme to catalyze the bond formation for the polymer construction, a reverse direction of the hydrolysis to cleave the bond. This catalysis is due to the enzymatic characteristics, where enzymes catalyze the reverse reaction involving a common intermediate in both forward and backward reactions. In nature, there are many polysaccharides having N-acetyl groups called mucopolysaccharides such as chitin, hyaluronic acid (HA), and chondroitin (Ch). 

The enzymatic chitin synthesis together with the TSAS concept provided with a new way for the synthesis of mucopolysaccharides having N-acetyl group at the 2-position of the sugar unit, which are widely found polysaccharides in nature. Scheme 35 explains that the MeOZO moiety in the monomer... 

Finally, the unprotected methyl oxazoline of D-glucosamine was used as a substrate for the glycosidase chitinase in the synthesis of the N,N -diacetylchitobiose, the repeating unit of chitin, via an enzymatic glycosylation [140],... 

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