TT_C1638 hemC 301 Hydroxymethylbilane synthase Tetrapolymerization of the monopyrrole PBG into the hydroxymethylbilane pre-uroporphyrinogen in several discrete steps. MRVVVVGTRGSALALAQTRFVVERLKETWPETEFKIRTIKTRGDQGASPREEAIFVKEIQEALLSREIDIAVHSLKDLPTESPRGLKIASVPRRQDPRDVFLGKAAKRLKDLPPGAVVGTSSVRRKAQILALRPDLVVRDLRGNVDTRLAALGNGEYDGIVLAAAGLIRLDLRNRIDEFLDPGEVLPAPGQGALALEVREGDDLAEELCYALHHPPSYHRVRAERAFLRGLGAGCLAPVGALAHVEEDGTLRLEGVLLTPDGKSFIRAEIEGDVSEAEELGLDLARDVLEQGGREILAQIR Pre-uroporphyrinogen synthase HEM3_THET2 Porphobilinogen deaminase