B4GALT3: Proteins and Enzymes

Several oligosaccharide structures and protein glycoconjugate types are found in nature. Homologous glycosyltransferase (GT) gene families catalyze the formation of glycosidic linkages. The beta-1,3 galactosyltransferase(beta3GalT) gene family encodes a set of type II transmembrane glycoproteins that are catalytically diverse and use different donor substrates (UDP-galactose and UDP-N-acetylglucosamine) and different acceptor sugars (N-acetylglucosamine, galactose, N-acetylgalactosamine ) to catalyze the addition of an activated monosaccharide to a terminal lactose. The protein coding sequences for beta-1,3-Gal-T genes comprise a single exon and are distantly related to the Drosophila Brainiac gene. The beta-1,4-galactosyltransferase (beta4GalT) gene family encodes type II membrane-bound glycoproteins that show exclusive specificity for the donor substrate, UDP-galactose. beta-1,4Gal-T genes transfer galactose in a beta-1,4 linkage to similar acceptor sugars; each gene has a distinct function in the biosynthesis of different glycoconjugates and saccharide structures.