Use of <i>Crithidia fasciculata</i> extract for the facile enzymatic synthesis of GDP-L-[3H]Fucose

For studies involving glycosyltransferases and nucleotide sugar transporters, radioactive nucleotide sugars are critical reagents. Of these, GDP-L-[3H]Fucose is currently commercially unavailable. Here, we present a facile approach for the preparation of GDP-[3H]-L-Fucose, using the enzymatic machinery present in the cytosol of the non-infectious and easily cultivated protozoan, Crithidia fasciculata, and its purification by solid phase extraction ion exchange chromatography.