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Updated: Jul 3, 2026

Activation and Conjugation of Soluble Polysaccharides using 1-Cyano-4-Dimethylaminopyridine Tetrafluoroborate (CDAP)
Published on: June 14, 2021
Novel carbonyl-group-containing dextran synthesis by pyranose-2-oxidase and dextransucrase
Hirokazu Seto1, Hidetaka Kawakita, Keisuke Ohto
1Faculty of Science and Engineering, Department of Applied Chemistry, Saga University, 1-Honjo Saga 840-8502, Japan.
Abstract:
The carbonyl polysaccharide, keto-dextran, was synthesized by the regioselective oxidation of sucrose and by the subsequent transfer reaction of the oxidized sucrose. The regioselective oxidation of sucrose was performed by bioconversion with pyranose-2-oxidase (EC 1.1.3.10). After 24h, the conversion percentage of sucrose into keto-sucrose was 100% as determined by a colorimetric method with dinitrophenylhydrazine. Converted keto-sucrose was polymerized to keto-dextran by dextransucrase (EC 2.4.1.5). Polymerization of keto-dextran was confirmed by the increase in molecular weight and amount of keto-dextran produced. The amount of keto-dextran produced decreased to 80% of the amount of dextran produced owing to the substrate recognition of DSase. From a Lineweaver-Burk reciprocal plot, the Michaelis constants for sucrose and keto-sucrose were 4.6 mmol L(-1) and 14.0 mmol L(-1), respectively. The keto-dextran had a carbonyl group in all glucose units.
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