Anti-STT3 oligosaccharyltransferase complex catalytic subunit A antibodies are used for the immunodetection of the protein encoded by the STT3A gene. In humans, the canonical protein has a reported length of 705 amino acid residues and a mass of 80.5 kDa. Its subcellular localization is in the ER. Alternative splicing is reported to yield 2 different isoforms for this protein. It is notably expressed at high levels in the placenta, liver, muscle and pancreas, and at very low levels in the brain, lung and kidney. A member of the STT3 protein family, it is a known catalytic subunit of the oligosaccharyl transferase (OST) complex that catalyzes the initial transfer of a defined glycan (Glc(3)Man(9)GlcNAc(2) in eukaryotes) from the lipid carrier dolichol-pyrophosphate to an asparagine residue within an Asn-X-Ser/Thr consensus motif in nascent polypeptide chains, the first step in protein N-glycosylation. Other names for this target antigen include CDG1WAR, ITM1, TMC, dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit STT3A, and CDG1WAD. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.