Substrate Specificity of Fucosyltransferase Purified from Human Parotid Saliva

The purified fucosyltransferase from human parotid saliva was shown to transfer fucose from GDP-fucose onto the oligosaccharide chains containing the Gal beta 1----3GlcNAc or Gal beta 1----4GlcNAc/Glc sequences. Competition studies between asialotransferrin and either lacto-N-fucopentaose 1 or 2'-fucosyllactose provided evidence that both the substrates competed for a common enzyme active site. These results suggest that the fucosyltransferase activities for the three acceptors may be catalyzed by the same enzyme.