Oligosaccharide formation

Asp, N. G., Burval, A., Dahlquist, A., Hallgren, P. and Lundblad, A. 1980. Oligosaccharide formation during hydrolysis of lactose with Saccaromyces lactis lactase (Maxi-lact R). II. Oligosaccharide structures. Food Chem. 5, 147-153. 

The mechanism whereby the chain-terminating step for oligosaccharide formation is regulated is not well understood. It has been proposed that certain structural features, such as the presence of sialyl or fucosyl residues, and an uncommon anomeric configuration,138,139 act as signals to halt the synthesis of the oligosaccharide chain. Additional studies are needed in order to clarify the role of these structural features in the chain-terminating process. 

Saunier B, Kilker RD, Tkacz JS, Quaroni A, Herscovics A. Inhibition of iV-finked complex oligosaccharide formation by... 

In oligosaccharide synthesis via transglycosylation the reaction is kinetically controlled, and the extent of oligosaccharide formation depends on the partition ratio of the glycosyl-enzyme intermediate between the transfer and hydrolytic reaction (Scheme 1). 

Glycosidase Oligosaccharide formation Anomeric selectivity Regio- and diastereo-selectivity, limited yields... 

Glycosidase Oligosaccharide formation AncHneric selectivity Region- and diasteroselectivity, equililHium State of tile art... 

The scheme describes asparagine linked oligosaccharide formation in liver but it also seems to be valid for other animal tissues (Adamany Spiro, 1975) and for insects (Quesada Allue, 1976) and probably plants. 

Blanchard and Albon observed some oligosaccharide formation when yeast enzyme was cillowed to act on melibiose. Later, a major component was identified as manninotriose by French. Courtois and Petek, studying coffee a-galactosidase, found that D-mannose and sucrose were active as acceptors for a-galactosyl residues, resulting in the formation of epimelibiose [0-a-D-galactopyranosyl-(i - 6)-D-mannose] and raffinose. 

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