Use of Water-Soluble Glycopolymer Synthesized by Polymerization

As an extension of this work, the authors applied the same approach to the preparation of free oligosaccharides, by introducing suitable, removable linker arms between the saccharide and the polymer backbone. Thus, radical copolymerization with acrylamide of monomers 36 and 37 having spacer-arms of different lengths, under the previous conditions, yielded water-soluble GlcNAc acceptor polymers 38 and 39, both having a linker selectively cleavable by hydrogenolysis [32, 33], Enzy- 

2 Enzymatic Synthesis of Glycolipids on Water-Soluble Polyacrylamide-Poly(A-acryloxysucdnimide) (PAN) 

The water-soluble polyacrylamide-poly(iV-acryloxysuccinimide) (PAN) first described by Whitesides for enzyme immobilization [35], was used by Zehavi et al. in 

Alternatively the polymer 51 carrying 0.24 meq lactosyl) (l-l)sphingosine g, chemically prepared from PAN, was sialylated in 55% yield by use of recombinant rat liver a(2-3)sialyltransferase, labeled CMP-NeuAc, and calf intestinal alkaline phosphatase [37]. Again photolysis of the 2-nitrobenzylurethane group in the sialylated polymer 52 followed by acylation with stearoyl chloride afforded the GM3 ganglioside, NeuAca(2-3)Gal)ff(l-4)Glc (l-l)Cer 53. 

In conclusion, compared with solution-phase synthesis, solid-phase enzymatic synthesis, generally, needs higher concentrations of enzyme, longer reaction times, and a large excess of donors. Although there is still room for improvement in terms of yields and scale-up of syntheses, in solid-phase synthesis purification procedures are straightforward so it is expected that this approach will open the route to automated oligosaccharide synthesis in the near future. 

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