Mannosyl Alpha-1,6-Glycoprotein Beta-1,6-N-Acetylglucosaminyltransferase Isozyme B (MGAT5B)

The MGAT5B gene encodes a beta-1,6-N-acetylglucosaminyltransferase (EC 2.4.1.155) that functions in the synthesis of complex cell surface N-glycans.The deduced 792-amino acid protein has a calculated molecular mass of 89.5 kD and shares 42% identity with GNT-VA. It contains an N-terminal cytoplasmic tail, a transmembrane domain, a stem region, a C-terminal catalytic domain, and 8 potential N-glycosylation sites. Northern blot analysis detected a 5-kb transcript exclusively in brain. RNA dot blot analysis detected GNT-IX in all specific adult brain regions examined and in fetal brain.GNT-IV transferred N-acetylglucosamine (GlcNAc) onto mannose substrates through a beta-1,6 linkage, and that it could modify both alpha-1,6-linked and alpha-1,3-linked mannose arms of core branched-chain N-glycans.