Enzymatic fucosylations

Fig. 8. Enzymatic fucosylation with integrated cofactor regeneration (Enzymes vi cf. Fig. 2, xi GDP-fucose-pyrophosphorylase, xii al-3/4-fucosyltransferase) [72]... 

The labeled GM3 trisaccharide, aNeu5NAc-(2 3)-/ Gal-(1 4)-Glc was prepared by sialylation of [U-13C]-lactose using pNPNeu5Ac as donor and a recombinant TcTS.161 The same authors synthesized, by enzymatic trans-sialylation of lactosa-mine, followed by enzymatic fucosylation, the sialyl Lewis X tetrasaccharide, aNeu5NAc-(2 3)-/ Gal-(1 4)[aFuc-(1 3)]GlcNAc. 

Fig. 13. Enzymatic fucosylations with FucT III to give Sialyl-Lewis ...

Interest in fucosylation of glycoconjugates is connected with higher fucosylation rates in aberrant tissue. Thus it was attempted to use enzymatic fucosylation processes to obtain fucosylated oligosaccharides. The isolation of a-L-fucosidase from porcine liver is performed, after... 

Very recently, in a related approach, Norberg et al. presented the solid-phase enzymatic fucosylation of a disacchaiide acceptor linked to Sepharose via a disulfide linkage and a linker arm of 12 atoms with a loading of 5 to 10 pmol disaccharide ligand mL wet gel [18]. The sepharose-bound disaccharide 10 incubated with human milk a(l-3/4)fucosyltransferase and GDP-Fuc in fivefold excess was converted into the Sepharose-bound trisaccharide 11 in 68% glycosylation yield (Scheme 4). The Lewis trisaccharide derivative 12 could be released from the matrix, together with the starting disaccharide 13, by treatment with 2-mercaptoetha-nol, in 91% yield. 

Murata, T., Morimoto, S., Zeng, X., Watanabe, S. and Usui, T. (1999) Enzymatic synthesis of alpha-L-fucosyl-N-acetyllactosamines and 3 -0-alpha-L-fucosyllactose utilizing alpha-L-fucosidases. Carbohydr Res, 320, 192-199. 

Faust, T., Theurer, C., Eger, K. and Kreis, W. (1994) Synthesis of uridine 5-(a-D-fucopyranosyl diphosphate) and (digitoxigenin-3(3-yl)-p-D-fucopyranosideand enzymatic p-D-fucosylation of cardenolide genins in Digitalis lanata. Bioorg. Chem., 22, 140-9. 

Starting from achiral materials, two stereoisomeric phosphonylated dihydroxy pyrrolidines (275) and (276), containing four stereogenic centers, have been synthesized enantioselectively, employing a combination of enzymatic and transition-metal-mediated methods. Both compounds contain features of the transition state of the enzyme-catalysed fucosyl transfer reaction and represent building blocks of potential inhibitors against this class of enzymes. The synthesis of new sugar-derived phosphonic acids e.g. (277) from protected... 

A number of non-natural fucosyl donors have also been probed with this enzyme [89]. As can be seen from Fig. 12, the C-6-atom of fucose is open for modifications. L-Gal and o-Ara are good substrates, whereas replacement of the 2-OH group of the fucose donor apparently is not tolerated by FucT VI. Indeed, Hindsgaul and coworkers succeeded in attaching the blood group A trisaccharide to the 6-position of the fucose donor and proved the biocatalytic transfer of this strange sugar [90]. The combination of non-natural donors with non-natural acceptors by enzymatic fucosyltransfer has also been probed which proved to be instrumental in the assembly of a library of sialyl-Lewis tetrasaccharides (Fig. 12) [91]. 

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