Natural polysaccharides are widely distributed in nature and thus considered as the very important biomass resources. The efficient methods for synthesis of functional polysaccharides have attracted much attention to provide new materials employed in application fields such as biomedical field. Enzymatic approaches have increasingly been important to precisely synthesize functional polysaccharide materials. Phosphorylase is one of the enzymes, which have been practically employed as catalysts for polysaccharides with well-defined structures. This enzyme catalyzes enzymatic polymerization of glucose 1-phosphate (Glc-1-P) as a monomer initiated from the nonreducing end of maltooligosaccharide primer to produce amylose. The author has reported that by means of the phosphorylase-catalyzed enzymatic polymerization using analog substrates as monomers, well-defined polysaccharides with functional groups such as amino and carboxylic acid groups are efficiently obtained.<sup> </sup>For example, phosphorylase isolated from thermophilic bacteria, <i>Aquifex aerolicus</i> VF5, catalyzed the enzymatic polymerization of glucosamine 1-phosphate (GlcN-1-P) as a monomer from maltotriose primer. The enzymatic reaction was accelerated in ammonia buffer containing magnesium ion, owing to the precipitation of inorganic phosphate, giving the high molecular weight aminopolysaccharide, which corresponded to chitosan stereoisomer (Figure 1). The thermostable phosphorylase-catalyzed enzymatic copolymerization of Glc-1-P with GlcN-1-P from maltotriose primer was also performed to produce unnatural glucosaminoglucans composed of α(1→4)-linked Glc/GlcN units. The enzymatic polymerization manner was applied to synthesize amphoteric block polysaccharide having both amino and carboxylic acid groups.

Synthesis of well-defined unnatural polysaccharides by phosphorylase-catalyzed enzymatic polymerization

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.