Galactosyltransferases catalyze the transfer of a galactosyl group to an acceptor molecule, typically another carbohydrate or a lipid, with either an alpha- or beta-linkage. Galactosyltransferases are involved in the synthesis of many oligosaccharides, glycoproteins and glycolipids of biological importance in eukaryotes. (Adapted from PMID:9603985.)