Beta-1,4-N-Acetyl Galactosaminyl Transferase 2 (b4GALNT2)

B4GALNT2 catalyzes the last step in the biosynthesis of the human Sd(a) antigen through the addition of an N-acetylgalactosamine residue via a beta-1,4 linkage to a subterminal galactose residue substituted with an alpha-2,3-linked sialic acid. B4GALNT2 also catalyzes the last step in the biosynthesis of the Cad antigen. The longer transcript encodes a deduced 566-amino acid protein with a calculated molecular mass of 63.3 kD. It contains an N-terminal cytosolic domain, followed by a transmembrane domain and a long catalytic domain. The shorter transcript encodes a deduced 506-amino acid protein with calculated molecular mass of 57.0 kD. It has a different N-terminal cytosolic domain than the full-length form. Northern blot analysis detected B4GALNT2 transcripts of 8.8, 6.1, 4.7, 3.8, and 1.65 kb.