GALNT2 is a family member of polypeptide N-acetyl-galactosaminyltransferases, which are responsible for initiating mucin type O-glycosylation by transferring GalNAc from UDP-GalNAc to Serine and Threonine residues of polypeptide acceptors. To date, there are about 20 members in this family of proteins. The characterization of peptide substrate specificity of each GALNT is critical in understanding their properties and biological roles. Biologically, trans-Golgi is the main subcellular location for GALNT2. This protein has a broad spectrum of peptide substrates peptides such as EA2, Muc5AC, Muc1a, and Muc1b. GALNT2 may play a role in lipid metabolism. In a whole-body and liver-specific GALNT2 knockout mice study, it was shown that whole-body GALNT2 deficiency resulted in elevated VLDL-triglycerides (TG) levels as compared to wild-type mice. GALNT2 KO mice did not exhibit differences in the post-prandial TG clearance or VLDL-TG secretion. In mice with liver-specific deletion, reduced HDL-Cholesterol and reduced numbers of HDL particles with minimal changes in plasma TG or dietary TG clearance were observed. These findings indicate that GALNT2 may play a role as a regulator of plasma lipoprotein metabolism with tissue-specific regulatory roles.