Over the past few years, glycosidases have been widely used for the preparation of a broad spectrum of glycoconjugates and derivatives employing either transglyco-sylation or reverse hydrolysis reactions . The synthetic use of glycosyltransfer-ases, especially of microbial origin, has so far been very limited. This is mainly due to two factors: low availability and high cost of both the enzymes and the nucleotide-sugar donor cofactors. Currently, only five glycosyltransferases, all eukaryotic in origin, are commercially available: a1,3-glucosyltransferase, ^1,4-galactosyltrans-ferase, a1,2-mannosyltransferase, a2,3-sialyltransferase, and a2,6-sialyltransferase. These range in price from $25/unit to as much as $1800/unit (unit is defined as the transfer of 1 ^mol of sugar from donor to acceptor in 1 min at 37°C). However, the
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