Novel carbonyl-group-containing dextran synthesis by pyranose-2-oxidase and dextransucrase.
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.
Seto
Hirokazu
H
Faculty of Science and Engineering, Department of Applied Chemistry, Saga University, 1-Honjo Saga 840-8502, Japan.
Kawakita
Hidetaka
H
Ohto
Keisuke
K
Harada
Hiroyuki
H
Inoue
Katsutoshi
K
D002237:Carbohydrate Dehydrogenases / Q000378:metabolism*; D002240:Carbohydrate Sequence; D003911:Dextrans / Q000138:chemical synthesis* / Q000737:chemistry*; D005964:Glucosyltransferases / Q000378:metabolism*; D007661:Ketoses / Q000138:chemical synthesis; D007700:Kinetics; D013395:Sucrose / Q000378:metabolism; D013997:Time Factors
D003911:Dextrans; D007661:Ketoses; D013395:Sucrose; D002237:Carbohydrate Dehydrogenases; C022489:pyranose oxidase; D005964:Glucosyltransferases; C020025:dextransucrase