Beta-4-Galactosyltransferase is involved in the formation of the poly-N-acetyllactosamine core structures present in glycoproteins and glycosphingolipids.
Beta-4-Galactosyltransferase transfers galactose from uridine diphosphogalactose to the terminal beta-N-acetylglucosamine residues, hereby forming the poly-N-acetyllactosamine core structures present in glycoproteins and glycosphingolipids. At least seven homologous beta-4-galactosyltransferase isoforms have been identified that use different types of glycoproteins and glycolipids as substrates. Of the seven identified members of the beta-1,4-galactosyltransferase subfamily (beta1,4-Gal-T1 to -T7), b1,4-Gal-T1 is most characterized (biochemically). It is a Golgi-resident type II membrane enzyme with a cytoplasmic domain, membrane spanning region, and a stem region and catalytic domain facing the lumen.