B3GALT5

Compared to other β3GalT enzymes, β3GalT5 (B3GALT5) has a synthetic activity for the strongest Type 1 carbohydrate antigen (Galb1-3GlcNAcb1-3-R). β3Gal-T5 was found to be expressed particularly in the gastrointestinal tract, and by the addition of the sialic acid and fucose to the Type 1 carbohydrate antigen, further greatly contributed to the synthesis of the Type 1 carbohydrate antigens, including the CA19-9 (sialyl Lewis a) antigen. In addition, β3GalT5 has a synthetic activity for Galβ1-3GlcNAcβ1-3GalNAc-O-Ser/Thru by the transfer of a galactose to core 3 O-linked glycans and a synthetic activity for carbohydrate conjugates, like Stage Specific Embryonic Antigen-3 (SSEA-3; Galβ1-3GalNAcβ1-3Galβ1-4Galβ1-4Glcβ1-1Cer).