title: Porphobilinogen-accumulating mutants of Salmonella typhimurium LT2.
abstract: Four independent porphobilinogen-accumulating mutants of Salmonella typhimurium LT2 were isolated by selecting for dwarf colony formation on neomycin agar media. Cell-free extracts of the parent strain, but not of the mutants, were able to convert 5-aminolaevulinic acid or porphobilinogen to porphyrins. The results indicated that the mutants were deficient in uroporphyrinogen I synthase (EC. 4.3.I. 8) activity: these are the first mutants of this type reported in S. typhimurium LT2. Mapping of the hemC locus (for uroporphyrinogen I synthase) by F-mediated conjugation and by P22-mediated transduction showed the gene sequence ilvEDAC-hemC-cya-metE.
mesh_terms: D000622:Aminolevulinic Acid / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002474:Cell-Free System; D002874:Chromosome Mapping; D003227:Conjugation, Genetic; D005796:Genes; D011163:Hydroxymethylbilane Synthase / Q000378:metabolism; D009154:Mutation; D011162:Porphobilinogen / Q000096:biosynthesis*; D011166:Porphyrins / Q000096:biosynthesis; D012486:Salmonella typhimurium / Q000201:enzymology / Q000378:metabolism*; D014161:Transduction, Genetic
chemical_list: D011166:Porphyrins; D011162:Porphobilinogen; D000622:Aminolevulinic Acid; D002374:Catalase; D011163:Hydroxymethylbilane Synthase