O antigen group O:56 repeat unit synthesis by glycosyltransferase reactions (lumped)
unaga_c + udpacgal_c + cdprib_c + dtdpacvioa_c ⇌ cdp_c + 2.0 udp_c + udcdpglcnac_a1_3_galnac_b1_4_rib_b1_3_qui4N_c