A-l,6-Glucosidic linkages

The formation of a-l,4-glucosidic linkages in vitro by plant enzymes was first demonstrated in 1940, when Hanes showed that potato tuber extracts formed an amylose-like product with glucose-l-P as a glucosyl donor (reaction 1). 

In the 1960s, L. F. Leloir, C. E. Cardini, and their collaborators in Buenos Aires, Argentina, demonstrated the synthesis of a-l,4-glucosidic linkages by... 

Lactose, a/ (l— 4) galactoside, induces cellulase in T. viride and a few other fungi. Sophorose, a/ (l—>2) glucoside, is a very powerful inducer of cellulase for T. viride only. These two sugars are the only known cellulase inducers that do not have a/ (l— 4) glucosidic linkage. 

In view of the specificity of the phosphorylase that disrupts the a-l,4-glucosidic linkages at the nonreducing end of glycogen, one might readily conceive that reversal of the phosphorylase reaction is responsible for glycogen synthesis. The thermodynamics of the phosphorylase reaction are not in conflict with such a hypothesis. 

P-Amylase (EC 3.2.1.2) is an exo-enzyme, occurring in a few microbes. It hydrolyses a-l,4-glucoside linkages from the non-reducing end of polysaccharides. It causes the... 

Using a similar reaction sequence P-(l—>4)-glucosidic linkages were very effectively installed on the support using 4-O-TBS-protected glucosyl phosphate donor 59. Thus, repetitive glycosylation and deprotection furnished trisaccharide 62 in 53% overall yield from 54 after cleavage from the resin (Scheme 6.11). 

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