ABO blood group (transferase A, alpha 1-3-N-acetylgalactosaminyltransferase; transferase B, alpha 1-3-galactosyltransferase)
fucgalacgalfucgalacglcgal14acglcgalgluside_hs_g + udpacgal_g ⇌ h_g + acgalfucgalacgalfucgalacglcgal14acglcgalgluside_hs_g + udp_g