α-Glucan phosphorylase-catalyzed enzymatic reactions using analog substrates to synthesize non-natural oligo-and polysaccharides

Abstract

As natural oligo-and polysaccharides are important biomass resources and exhibit vital biological functions, non-natural oligo-and polysaccharides with a well-defined structure can be expected to act as new functional materials with specific natures and properties. α-Glucan phosphorylase (GP) is one of the enzymes that have been used as catalysts for practical synthesis of oligo-and polysaccharides. By means of weak specificity for the recognition of substrates by GP, non-natural oligo-and polysaccharides has precisely been synthesized. GP-catalyzed enzymatic glycosylations using several analog substrates as glycosyl donors have been carried out to produce oligosaccharides having different monosaccharide residues at the non-reducing end. Glycogen, a highly branched natural polysaccharide, has been used as the polymeric glycosyl acceptor and primer for the GP-catalyzed glycosylation and polymerization to obtain glycogen-based non-natural polysaccharide materials. Under the conditions of removal of inorganic phosphate, thermostable GP-catalyzed enzymatic polymerization of analog monomers occurred to give amylose analog polysaccharides.