B4GALT3

This gene encodes beta-1,4-galactosyltransferase 3 that is involved in the synthesis of the Type 2 carbohydrate antigen (Galb1-4GlcNAc-R). This enzyme has the activity that transfers a Gal from the donor UDP-Gal to the GlcNAc of the non-reducing terminal of the acceptor by the b1-4 bond. The GlcNAcb1-4Man (synthesized by MGAT4) has the highest specificity (reactivity) to the agalacto type N-linked oligosaccharides (4-chain). First, it transfers a galactose to this position, after that it tends to transfer a galactose to GlcNAcb1-2Man (synthesized by MGAT1) and then to GlcNAcb1-4Man (synthesized by MGAT2). It is also involved in the biosynthesis of the type 2 chain glycolipids (Galb1-4GlaNAcb1-3Galb1-4Glca-Cer).