Does GalactEXO digest fucosylated glycan structures such as Lewis X or Lewis a?

No. Branching fucose linked to the same residue as the β-galactose inhibits GalactEXO activity and needs to be removed prior to GalactEXO treatment. The FucosEXO enzyme can be used for hydrolysis of α1-2, α1-3 and α1-4 linked fucose.