Hydroxymethylbilane synthase Pre-uroporphyrinogen synthase MTH_874 Tetrapolymerization of the monopyrrole PBG into the hydroxymethylbilane pre-uroporphyrinogen in several discrete steps. 289 hemC Probable porphobilinogen deaminase HEM3_METTH MIAGTRGSRLALVQTNHVIEMLSEVCKEKIEKKIIKTKGDRIRDSQLYSMDSRGLFTRELDMAVLNEEVDLAVHSLKDVPSDLDPDLAIAAVPPRESPAEVLVSRLDWEDLPQGSKLGTSSLRREAFCNHHQKNFKMEPLRGNIDTRIRKVMDGEVHATIMAEAGLKRLGLEEHIKRRFPVEYFTPAAGQGALAVITRADSELISSIGRITHHPSLQEVTAEKTLLRELGAGCQCPLGVIGRATGNQLTLYAVLLTREGEMLRKVTVRGPLAEAEDIGKKAAKEMEDYI