May be involved in cell wall synthesis. Catalyzes alpha-1,4 glycosidic linkages and generates Lewis-a epitopes. Protein modification; protein glycosylation. Membrane-bound form in trans cisternae of Golgi. Present in root, stem, flower buds and green siliques. Belongs to the glycosyltransferase 10 family. It is uncertain whether Met-1 or Met-9 is the initiator.