Beta-1,4-galactosyltransferase 1 (B4GALT1)

Beta-1,4-galactosyltransferase 1 (B4GALT1) is a glycosyltransferase enzyme that catalyzes the transfer of galactose from UDP-galactose to N-acetylglucosamine (GlcNAc) residues on glycoproteins and glycolipids, forming a β(1→4) linkage. It plays a crucial role in the biosynthesis of complex glycoconjugates and is essential for proper protein glycosylation, which is critical for various cellular processes, including cell-cell recognition, signaling, and immune response. In lactating mammary glands, it forms a heterodimer with α-lactalbumin to synthesize lactose. Defects in B4GALT1 can cause congenital disorder of glycosylation type II D (CDG2D), leading to multisystemic symptoms.