Chitinase‐Catalyzed Synthesis of a Chitin‐Xylan Hybrid Polymer: A Novel Water‐Soluble β(1 → 4) Polysaccharide Having an N‐Acetylglucosamine‐Xylose Repeating Unit

Abstract

Summary: A chitin‐xylan hybrid polysaccharide having β(1 → 4)‐linked alternating structure of N‐acetyl‐D‐glucosamine and D‐xylose was synthesized via chitinase‐catalyzed polymerization. An oxazoline derivative of D‐xylosyl‐β(1 → 4)‐N‐acetyl‐D‐glucosamine (1) was effectively polymerized by the catalysis of chitinase from Bacillus sp., giving rise to a water‐soluble chitin‐xylan hybrid polysaccharide (2) in good yields. Molecular weights ($\overline M _{\rm n}$) of 2 reached 1 500, which corresponds to 8–10 saccharide units.A chitin‐xylan hybrid polysaccharide (2) synthesized via chitinase‐catalyzed polymerization.magnified imageA chitin‐xylan hybrid polysaccharide (2) synthesized via chitinase‐catalyzed polymerization.

Enzymes as Green Catalysts for Precision Macromolecular Synthesis

“…Similarly, chitin-xylan hybrid polysaccharide having an alternating GlcNAc and Xyl was prepared from Xylβ(1→4)­GlcNAc oxazoline monomer with chitinase catalyst, which generated water-soluble polysaccharide of a mass weight larger than 1.0 × 10 4 (R 1 = R 3 = R 4 = OH, R 2 = CH 2 OH, R 5 = H in Scheme ). This sort of preparation of unnatural hybrid polysaccharide was extended to chitin-chitosan which has a regular alternating sequence of GlcNH 2 and GlcNAc (R 1 = R 4 = OH, R 2 = R 5 = CH 2 OH, R 3 = NH 2 in Scheme ). …”

“…Similarly, chitin-xylan hybrid polysaccharide having an alternating GlcNAc and Xyl was prepared from Xylβ(1→4)GlcNAc oxazoline monomer with chitinase catalyst, which generated water-soluble polysaccharide of a mass weight larger than 1.0 × 10 4 (R 1 = R 3 = R 4 = OH, R 2 = CH 2 OH, R 5 = H in Scheme 52). 617 This sort of preparation of unnatural hybrid polysaccharide was extended to chitin-chitosan which has a regular alternating sequence of GlcNH 2 and GlcNAc (R 1 = R 4 = OH, R 2 = R 5 = CH 2 OH, R 3 = NH 2 in Scheme 52). 618 620,621 Fluorine-substituted chitobiose oxazoline derivatives having C-6 fluorine (R 1 = R 4 = OH, R 2 = CH 2 F, R 3 = NHAc, R 5 = CH 2 OH in Scheme 52) were polymerized by the chitinase catalyst, giving rise to white precipitates of structurally welldefined fluorinated-chitins with average molecular weights of Fchitins of 1400−1700.…”

Enzymatic Polymer Synthesis: An Opportunity for Green Polymer Chemistry

“…Synthesis of a chitin−xylan hybrid polysaccharide was performed using a Xylβ(1→4)GlcNAc oxazoline TSAS monomer with chitinase catalyst (Scheme c) . The resulting polysaccharide showed good solubility in water, and no precipitate was observed during the polymerization.…”

Precision Polysaccharide Synthesis Catalyzed by Enzymes

“…A chitin−xylan hybrid polysaccharide was synthesized by chitinase-catalyzed ring-opening polyaddition of Xyl-β-(1→4)-GlcNAc oxazoline monomer (Scheme b) . The resulting polysaccharide showed good solubility in water.…”