Takao Raku, Yutaka Tokiwa
National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba
Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan

　Carbohydrates are useful natural resources for the development of new high performance materials. Various types of vinyl sugars have been developed using chemical catalysts. However, previously known vinyl sugars or vinyl nucleosides have acrylate, methacrylate and styrene as polymerizable groups and these are not biodegradable after polymerization. Enzymatic modification of sugars and nucleosides offers a highly efficient process compared with conventional chemical synthesis.Enzymatic reactions that produce new materials are attractive for their regio-selectivityand their environmentally friendly properties.
    In this paper, we investigated synthesis of biodegradable sugar- (or nucleoside-) branched polymers consisting of sugar (or nucleoside), fatty acid and poly(vinyl alcohol) by a chemoenzymatic method.
    Hexoses (D-glucose, D-mannose, D-galactose and D-allose) were esterified with divinyladipate by alkaline protease to give corresponding 6-O-vinyl adipoyl sugars. In the presence denaturating co-solvent, DMSO, galactose and allose were selectively esterified at only the C-2 position. Transesterification reactions of hydroxyl group of ribose moiety in nucleoside with divinyladipate were catalyzed by alkaline proteases to
give vinyl nucleosides. Poly(vinyl alcohol) containing nucleoside branches could be obtained by their free-radical polymerization. Polymers that have sugar and nucleoside branches would be useful as functional materials in various fields.

    论文来源：1st International Conference on Technology and Application of Biodegradable Polymers and Plastics,October,2004