Substrate and donor specificity of glycosyl transferases.

It has been shown that all selectins recognize the carbohydrate epitopes sialyl Lewis(x) and sialyl Lewis(a). For the establishment of the structure-activity relationship, the efficient synthesis of these tetrasaccharides and derivatives is therefore of vital interest. The glycosyl transferase-mediated approach is summarized with emphasis on the use of modified acceptors and modified sugar-nucleotide donors. A survey of the involved enzymes: beta(1-3) and beta(1-4)galactosyl transferases, alpha(2-3)sialyl transferase, FucT III and FucT VI reveals that the enzymatic synthesis is highly efficient for the rapid preparation of sialyl Lewis(x)- and sialyl Lewis(a)-derivatives.