linguistic:translation, information:highlighting, quality:correction
Structural studies

GALT also has minimal (~0.1%) GalNAc transferase activity. X-ray crystallography revealed that the side chain of Tyr289 forms a hydrogen bond with the N -acetyl group of UDP-GalNAc. Point mutation of residue Tyr289 to Leu, Ile, or Asn eliminates this interaction, enhancing GalNAc transferase activity, with the Y289L mutation showing comparable GalNAc transferase activity as the wild-type enzyme's Gal transferase activity.