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We present a novel approach to constructing glycosylated surface for microporous membrane. Carbohydrate derivative can be facilely bound onto the alkyne-modified membrane surface via thiol-yne click chemistry. The glycosylated membrane surface shows an excellent affinity adsorption to lectin on the basis of carbohydrate-protein recognition.

A versatile approach based on click chemistry to synthesize polyphosphazene glycopolymers is presented. The glucose‐substituted polyphosphazene was synthesized by nucleophilic substitution of poly(dichlorophosphazene) with propargylamine and the subsequent azide/alkyne “click” reaction of poly[di(propargylamine)phosphazene] (PDPAP) with azidosugar. The relative proportion of the glucose substituent can be easily controlled over a broad range by varying the amount of azidoglucose used in the azide/alkyne “click” reaction. magnified image

To biologically mimic the carbohydrate-protein interactions in artificial systems, one of the challenges is to construct a glycosylated surface with a high glycosyl density to yield a notable 'glycoside cluster effect'. A novel strategy is presented for high density glycosylation of the surface of a microporous poly(propylene) membrane (MPPM) by click chemistry. It is promising that the surface glycosyl density can be well controlled over a wide range and the maximum value is over 10 µmol · cm(-2) . The recognition capability of these glycosylated MPPMs to lectins indicates the occurrence of the 'glycoside cluster effect' when the glycosyl density on the membrane surface exceeds 0.20 µmol · cm(-2) .

We describe a versatile approach to synthesize glycosylated polyphosphazenes with controllable density of glycosyl groups. These glycopolymers have been synthesized by the nucleophilic substitution of poly(dichlorophosphazene) with propargylamine and subsequent “thiol–yne” click reaction between poly[di(propargylamine)phosphazene] and 2,3,4,6‐tetra‐O‐acetyl‐1‐thio‐β‐D‐glucopyranose (SH‐GlcAc4). The polymers were characterized with FTIR and 1H NMR. We found that the high steric hindrance of SH‐GlcAc4 plays a key role in the overall reaction process, and ∼55% of the alkyne groups participate in the “thiol–yne” click reaction. About 8% of the alkyne groups convert to alkene groups at the end of click reaction. The substitution of alkyne/alkane mixture was conducted to reduce the alkyne density in the side groups of polyphosphazenes and minimize the influences of this steric effect. Mixed‐substituent polyphosphazene was synthesized with 2:3 ratio of alkyne and alkane. In this case, almost no alkyne group remains after the “thiol–yne” click reaction, and thus the glycosylated polyphosphazene is able to form into micelles through self‐assembly process. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

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Dextranase specifically hydrolyzes dextran and is used to produce functional isomalto-saccharide prebiotics. Moreover, dextranase is used as an additive in mouthwash to remove dental plaque. We cloned and expressed the dextranase gene of the marine bacterium Bacillus aquimaris S5. The length of the BaDex gene was 1788 bp, encoding 573 amino acids. Using bioinformatics to predict and analyze the amino acid sequence of BaDex, we found the isoelectric point and instability coefficient to be 4.55 and 29.22, respectively. The average hydrophilicity (GRAVY) was -0.662. The secondary structure of BaDex consisted of 145 alpha helices, accounting for 25.31% of the protein; 126 extended strands, accounting for 21.99%; and 282 random coils, accounting for 49.21%. The 3D structure of the BaDex protein was predicted and simulated using SWISS-MODEL, and BaDex was classified as a Glycoside Hydrolase Family 66 protein. The optimal temperature and pH for BaDex activity were 40°C and 6.0, respectively. The hydrolysates had excellent antioxidant activity, and 8 U/mL of BaDex could remove 80% of dental plaque in MBRC experiment. This recombinant protein thus has great promise for applications in the food and pharmaceutical industries.