Glucosaminyl-N-Acetyl Transferase 2 (GCNT2)

GCNT2 encodes the enzyme responsible for formation of the blood group I antigen. The i and I antigens are distinguished by linear and branched poly-N-acetyllactosaminoglycans, respectively. The encoded protein is the I-branching enzyme, a beta-1,6-N-acetylglucosaminyltransferase responsible for the conversion of fetal i antigen to adult I antigen in erythrocytes during embryonic development. Alternatively spliced transcript variants encoding different isoforms have been described. Comparison of the amino acid sequence with those of other glycosyltransferases revealed that this I-branching enzyme and another beta-1,6,N-acetylglucosaminyltransferase that forms a branch in O-glycans (GCNT1) are strongly homologous in the center of their putative catalytic domains.