Oligosaccharides transferases

Branch points are degraded by the concerted action of an oligosaccharide transferase and an a-l,6-glucosidase. 

Figure 47-9. Schematic pathway of oligosaccharide processing. The reactions are catalyzed by the following enzymes , oligosaccharideiprotein transferase , a-glucosidase I ...

The oligosaccharide GICjMangCGIcNAcjj is transferred from dolichol-P-P-oligosaccharide in a reaction catalyzed by oligosaccharide protein transferase, which is inhibited by tunicamycin. 

Tunicamycin Inhibits GIcNAc-P transferase, the enzyme catalyzing addition of GIcNAc to dolichol-P, the first step in the biosynthesis of oligosaccharide-P-P-dolichol... 

Oxidoreductases Transferases Hydrolases Lyases Isomerases Ligases Phenolic polymers, polyanilines, vinyl polymers Polysaccharides, cyclic oligosaccharides, polyesters Polysaccharides, polyesters, polycarbonates, poly(amino acid)s, polyphosphates... 

High selectivity and substrate specificity of glycosyl transferases make them valuable catalysts for special linkages in polymer-supported synthesis. There is, however, still a rather limited set of enzymes available to date, and the need to synthesize a variety of natural and non-natural oligosaccharides prevails. Particularly with regard to combinatorial approaches, chemical solid-phase oligosaccharide synthesis promises to meet the demands most effectively. 

Scheme 10.2 Oligosaccharide synthesis and a-chymotrypsin catalyzed release from the solid support, a) Z-Phe-NH-(CH2)6-OH (7), CSA, (CHCljjz, 70°C b) Hj, Pd/C, MeOH, 50°C c) CH2 = CHCONH(CHjjsCOOH (8), EtOH-CeHe d) MeONa (cat.), MeOH/THF, CH2 = CHCONH2, TMEDA, APS, DMSO-H2O, SOT e) Galactosyl transferase, Sialyl transferase g) CT, Tris-HCI buffer, pH 7.8, 48 °C, 72% from (10).

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