Enzyme kinetics glycosyl transfer

STEREOCHEMISTRY AND STEADY-STATE KINETICS OE ENZYMIC GLYCOSYL TRANSFER... 

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). 

Enzyme intermediates trapped by chemical modification can provide pertinent details about the enzyme active site and catalytically significant amino acids that directly reflect on the reaction mechanism. However, when the chemical modification is irreversible, demonstrating kinetic relevance by intermediate transfer along the remainder of the reaction pathway at a rate consistent with catalysis is not possible. Thus, distinguishing an authentic covalent intermediate from a collapsed form of a glycosyl-cation is not possible. 

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