alpha-1,3-mannosyl-glycoprotein 4-beta-N-acetylglucosaminyltransferase B; UDP-N-acetylglucosamine:alpha-1,3-D-mannoside beta-1,4-N-acetylglucosaminyltransferase IVb; N-glycosyl-oligosaccharide-glycoprotein N-acetylglucosaminyltransferase IVb; N-acetylglucosaminyltransferase IVb, GnT-IVb, GlcNAc-T IVb (MGAT4B)

Function

• glycosyltransferase
• role in transfer of N-acetylglucosamine (GlcNAc) to the core mannose residues of N-linked glycans
• catalyzes formation of GlcNAcbeta1-4 branch on GlcNAcbeta1-2Manalpha1-3 arm of the core structure of N-linked glycans
• essential for the production of tri- & tetra-antennary N-linked sugar chains
• has lower affinities for donors or acceptors than MGAT4A, thought not main contributor in N-glycan biosynthesis

Cofactor: divalent metal cations

Kinetic parameters:

• KM=0.242 mM for UDP-GlcNAc

Structure

belongs to the glycosyltransferase 54 family

Compartment

Golgi

Alternative splicing

named isoforms=2

Expression

widely expressed

Pathology

• strongly overexpressed in pancreatic cancer

More general terms

• UDP-N-acetylglucosamine:alpha-1,3-D-mannoside beta-1,4-N-acetylglucosaminultransferase

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=11282
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:11282
• OMIM: https://mirror.omim.org/entry/604561
• UniProt: http://www.uniprot.org/uniprot/Q9UQ53.html