Glycosyltransferase acceptor specificities

Seibel J, Hellmuth H, Hofer B, Kicinska AM, Schmalbruch B (2006) Identification of new acceptor specificities of glycosyltransferase R with the aid of substrate microarrays. Chem-biochem 7 310-320... 

Oligosaccharide chains linked by 0-glycosidic bonds to seryl or threonyl residues show more structural variability than do the asparagine-linked oligosaccharides the serine (threonine)-linked oligosaccharides range in size from 1 to 20 or more monosaccharide residues. The residues are added one at a time, directly on the protein, rather than preassembled on a lipid carrier. Assembly is not random, however, and the glycosyltransferases involved have acceptor specificities that render certain structures preferable. 

This chapter reviews the literature on enzymatic synthesis utilizing Leloir glycosyltransferases, with focus on galactosyltransferases, fucosyltransferases, and sia-lyltransferases, most of which are commercially available or widely accessible. Also, they are well studied in terms of their donor and acceptor specificity and have been used for the synthesis of both natural oligosaccharides and their analogs. As well, two practical examples for the synthesis of trisaccharide analogs are given. 

The enzyme(s) were purified 60-fold to 220-fold and were shown to have no metal requirement, nor did they require detergent for activity (membrane-bound glycosyltransferases require detergents). Table II shows the acceptor specificity study for this enzyme(s). 

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