O-antigen group O:63 polymerase yielding a very long O antigen chain length (100 repeat units)
100.0 udcdpgalnac_a1_3_galnac_a1_4_glc_b1_4_gal_a1_4_fuc3nac_p ⇌ 99.0 udcpdp_p + OA63_VL_p