Function
Glycopeptide transferase involved in O-linked oligosaccharide biosynthesis, which catalyzes the transfer of an N-acetyl-D-galactosamine residue to an already glycosylated peptide (PubMed:11925450, PubMed:12829714). In contrast to other proteins of the family, it does not act as a peptide transferase that transfers GalNAc onto serine or threonine residue on the protein receptor, but instead requires the prior addition of a GalNAc on a peptide before adding additional GalNAc moieties (PubMed:11925450). Some peptide transferase activity is however not excluded, considering that its appropriate peptide substrate may remain unidentified. Prefers the monoglycosylated Muc5AC-3 as substrate (PubMed:11925450). Might have a role in protein O-glycosylation in the Golgi and thereby in establishing and/or maintaining a proper secretory apparatus structure (PubMed:20807760).
Sequence
MRVSTIRSGRICRLALCLLVLLPLLYLLANWSDHHKRVQEAYHTRFGGPKFAHQRLEGRPREVPKLVDGLGNFEPKDVKPRSGPGENGEAHSLSPDKKHMSDASEMEYGMNIACSDEISMHRSVRDTRLEECRHWDYPFDLPRTSVIIVFHNEGFSVLMRTVHSVIDRSPTHMLHEIILVDDFSDKENLRSQLDEYVLQFKGLVKVIRNKEREGLIRTRSRGAMEATGEVIVFLDAHCEVNTNWLPPLLAPIYRDRTVMTVPIIDGIDHKNFEYRPVYGTDNHFRGIFEWGMLYKENEVPRREQRRRAHNSEPYRSPTHAGGLFAINREYFLELGAYDPGLLVWGGENFELSFKIWQCGGSIEWVPCSRVGHVYRGFMPYNFGKLASKKKGPLITINYKRVIETWFDDTHKEYFYTREPLARYLDMGDISEQLALKKRLNCKSFQWFMDHIAYDVYDKFPGLPANLHWGELRSVASDGCLDSMGHQPPAIMGLTYCHGGGNNQLVRLNAAGQLGVGERCVEADRQGIKLAVCRLGTVDGPWQYNEHTKHLMHRVHKKCMALHPATQQLSLGHCDVNDSYQQWWFKEIRPRW