Enzymatic Polymerization to Novel Polysaccharides Having a Glucose-<i>N</i>-acetylglucosamine Repeating Unit, a Cellulose−Chitin Hybrid Polysaccharide

Kobayashi, Shiro; Makino, Akihiro; Matsumoto, Hironori; Kunii, Shigeru; Ohmae, Masashi; Kiyosada, Toshitsugu; Makiguchi, Ken; Matsumoto, Akira; Horie, M.; Shoda, Shin Ichiro

doi:10.1021/bm060094q

Cited by 63 publications

(43 citation statements)

References 47 publications

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“…[28] Some of these polymers had not been successfully synthesized via conventional polymerization; that is, enzymatic polymerization enabled their in vitro synthesis for the first time, as exemplified by cellulose, [29] chitin, [30] xylan, [31] hyaluronan, [32] chondrotin, [33] unnatural hybrid polysaccharides, [34] and polyphenol and its derivatives. [35] Lipase-catalyzed polyester synthesis is one of the most well-known topics, which has been very actively studied.…”

Section: Introductionmentioning

confidence: 99%

Recent Developments in Lipase‐Catalyzed Synthesis of Polyesters

Kobayashi

2009

Macromol. Rapid Commun.

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Polyester synthesis by lipase catalyst involves two major polymerization modes: i) ring-opening polymerization of lactones, and, ii) polycondensation. Ring-opening polymerization includes the finding of lipase catalyst; scope of reactions; polymerization mechanism; ring-opening polymerization reactivity of lactones; enantio-, chemo- and regio-selective polymerizations; and, chemoenzymatic polymerizations. Polycondensation includes polymerizations involving condensation reactions between carboxylic acid and alcohol functional groups to form an ester bond. In most cases, a carboxylic acid group is activated as an ester form, such as a vinyl ester. Many recently developed polymerizations demonstrate lipase catalysis specific to enzymatic polymerization and appear very useful. Also, since lipase-catalyzed polyester synthesis provides a good opportunity for conducting "green polymer chemistry", the importance of this is described.

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Section: Introductionmentioning

confidence: 99%

Recent Developments in Lipase‐Catalyzed Synthesis of Polyesters

Kobayashi

2009

Macromol. Rapid Commun.

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254

205

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“…[22,23] Very recently, hybrid GAGs that are composed of HA, Ch and Ch-4-sulfate have been prepared via hyaluronidase-catalyzed copolymeriza-tions. [24] In these polymerizations, synthetic carbohydrate monomers that are activated at the anomeric carbons by fluorine atoms [17,20] or a dihydrooxazole (oxazoline) structure [18][19][20][21][22][23][24] were enzymatically polymerized in a perfectly regioselective and stereocontrolled fashion. Particularly, the sugar oxazoline derivatives were designed for the catalysis by the enzymes that use sugar oxazolinium ions as transition states during the hydrolysis reactions.…”

Section: Introductionmentioning

confidence: 99%

Keratanase II‐Catalyzed Synthesis of Keratan Sulfate Oligomers by Using Sugar Oxazolines as Transition‐State Analogue Substrate Monomers: A Novel Insight into the Enzymatic Catalysis Mechanism

et al. 2007

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Keratan sulfate (KS) oligomers with well-defined structures were synthesized by keratanase II (KSase II)-catalyzed transglycosylation. N-Acetyllactosamine [Galbeta(1-->4)GlcNAc; LacNAc] oxazoline derivatives with sulfate groups at the C-6 (1 a) and both the C-6 and the C-6' (1 b) were prepared as transition-state analogue substrate monomers for KSase II. Monomer 1 a was effectively oligomerized by the enzyme under weak alkaline conditions, to give alternating 6-sulfated KS oligomers (2 a) in good yields, and with total control of regioselectivity and stereochemistry. KSase II also recognized 1 b, which provided fully 6-sulfated KS oligomers (2 b) in good yields under similar conditions. Nonsulfated LacNAc oxazoline was difficult to oligomerize enzymatically. These results imply that the catalysis mechanism of KSase II involves a sugar oxazolinium ion that requires the 6-sulfate group in the GlcNAc residue not only in hydrolysis of KS chains, but also in oligomerization of oxazoline monomers. This is the first report of KSase II-catalyzed transglycosylation to form beta(1-->3)-glycosidic bond through a substrate-assisted mechanism.

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“…Interestingly, the enzyme produced the hybrid polysaccharide under various pH conditions ranging from 3.0 to 7.0 with M n 2,600-2,800, corresponding to 15-16 saccharide units, in good yields (Table 3). 69) A mechanism for the polycondensation by cellulase catalysis is similarly considered as that of the cellulose synthesis; however, it is strange that monomer ChiCe-F with a bulky N-acetyl group at C2 was still recognized, activated, and glycosy- …”

Section: )mentioning

confidence: 99%

New developments of polysaccharide synthesis via enzymatic polymerization

Kobayashi

2007

Proceedings of the Japan Academy. Ser. B: Physical and Biologic

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This review focuses on the in vitro synthesis of polysaccharides, the method of which is ''enzymatic polymerization'' mainly developed by our group. Polysaccharides are formed by repeated glycosylation reactions between a glycosyl donor and a glycosyl acceptor. A hydrolysis enzyme was found very efficient as catalyst, where the monomer is designed based on the new concept of a ''transition-state analogue substrate'' (TSAS); sugar fluoride monomers for polycondensation and sugar oxazoline monomers for ring-opening polyaddition. Enzymatic polymerization enabled the first in vitro synthesis of natural polysaccharides such as cellulose, xylan, chitin, hyaluronan and chondroitin, and also of unnatural polysaccharides such as a cellulose-chitin hybrid, a hyaluronan-chondroitin hybrid, and others. Supercatalysis of hyaluronidase was disclosed as unusual enzymatic multi-catalyst functions. Mutant enzymes were very useful for synthetic and mechanistic studies. In situ observations of enzymatic polymerization by SEM, TEM, and combined SAS methods revealed mechanisms of the polymerization and of the self-assembling of high-order molecular structure formed by elongating polysaccharide molecules.

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Enzymatic Polymerization to Novel Polysaccharides Having a Glucose-N-acetylglucosamine Repeating Unit, a Cellulose−Chitin Hybrid Polysaccharide

Cited by 63 publications

References 47 publications

Recent Developments in Lipase‐Catalyzed Synthesis of Polyesters

Recent Developments in Lipase‐Catalyzed Synthesis of Polyesters

Keratanase II‐Catalyzed Synthesis of Keratan Sulfate Oligomers by Using Sugar Oxazolines as Transition‐State Analogue Substrate Monomers: A Novel Insight into the Enzymatic Catalysis Mechanism

New developments of polysaccharide synthesis via enzymatic polymerization

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