Alpha-1,4-N-Acetylglucosaminyltransferase 4, also known as A4GNT is a 45 kDa glycoprotein, member of the glycosyltransferase 32 family of proteins. A4GNT catalyzes the transfer of N-acetylglucosamine (GlcNAc) to core 2 branched O-glycans. A4GNT is a single-pass type II membrane protein associated with the Golgi apparatus and contains the conserved DXD motif involved in catalytic activity. It is expressed in stomach and pancreas, as well as in gastric cancer cells. A4GNT is not expressed in peripheral blood cells, making it a putative biomarker for pancreatic cancer. A4GNT and Mucin 6 expression is upregulated in the gastric mucosa of H. pylori infected patients. Lumenal domain of human A4GNT shares 72% aa sequence identity with mouse and rat A4GNT.