1H NMR spectroscopy
Springer Online Journal Archives 1860-2000
Chemistry and Pharmacology
Abstract α-Glucosidase I is a key enzyme in the biosynthesis of asparagine-linked oligosaccharides catalyzing the first processing event after the en bloc transfer of Glc3Man9GlcNAc2 to proteins. This enzyme is an inhibitor target for anti-viral agents that interfere with the formation of essential glycoproteins required in viral assembly, secretion and infectivity. Of fundamental mechanistic interest for all oligosaccharide hydrolyzing enzymes is the stereochemical course of the reaction which can occur with either retention or inversion of anomeric configuration. The stereochemistry is used to categorize enzymes and is important in designing mechanism-based inhibitors. To determine the stereochemical course of the α-glucosidase I reaction, the release of glucose from a synthetic trisaccharide substrate, Glc(α1-2)Glc(α1-3)GlcαO(CH2)4COOCH3 was directly monitored by 1H NMR spectroscopy. Both the yeast and bovine mammary gland enzymes released β-glucose concomitant with the formation of the Glc(α1-3)GlcαO(CH2)8COOCH3 disaccharide product demonstrating that both enzymes operate with inversion of anomeric configuration.
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