In enzymology, a beta-glucogallin O-galloyltransferase () is an enzyme that catalyzes the chemical reaction
Hence, this enzyme has one substrate, 1-O-galloyl-beta-D-glucose, and two products, D-glucose and 1-O,6-O-digalloyl-beta-D-glucose.
This enzyme belongs to the family of transferases, specifically those acyltransferases transferring groups other than aminoacyl groups. The systematic name of this enzyme class is 1-O-galloyl-beta-D-glucose:1-O-galloyl-beta-D-glucose O-galloyltransferase.