Glycosyltransferases (abbre. GTFs, Gtfs) are enzymes (EC 2.4) that establish natural glycosidic linkages a wide range of small and macromolecules including cell wall components, natural products, other saccharides, proteins and even nucleic acids. They catalyse the transfer of saccharide moieties from activated nucleotide sugar (also known as the "glycosyl donor") to a nucleophilic glycosyl acceptor molecule, the nucleophile of which can be oxygen- carbon-, nitrogen-, or sulfur-based.