Anti-GCNT2 antibodies are used in the immunodetection of the protein glucosaminyl (N-acetyl) transferase 2 (I blood group). In humans, the canonical protein has a reported length of 402 amino acid residues and a mass of 45.9 kDa. Its subcellular localization is in the golgi. Alternative splicing is reported to yield 3 different isoforms for this protein. A member of a the Glycosyltransferase 14 protein family, GCNT2 is reported to be a branching enzyme that converts linear into branched poly-N-acetyllactosaminoglycans. Post-translational modifications have been described, including glycosylation. Synonyms for this target antigen include CTRCT13, GCNT2C, GCNT5, IGNT, II, NACGT1, NAGCT1, and CCAT.