We describe glycosyltransferase nucleic acids and proteins isolatable from Arabidopsis thaliana, transgenic cells expressing said glycosyltransferases, and bioreactors comprising said transgenic cells together with nutrient medium for supporting the growth of said cell that includes at least one exogenous substrate which is a substrate for said glycosyltransferase, and wherein said nutrient medium does not include an exogenous supply of UDP-glucose.