O-antigen group O:51 polymerase yielding a long O antigen chain length (25 repeat units)
25.0 udcdpglcnac_a1_3_galnac_b1_3_gal_b1_3_glcnac_a1_4_glc_p ⇌ 24.0 udcpdp_p + OA51__L_p