title: Isolation of haemin-requiring mutants of Escherichia coli K12.
abstract: Fifty-five haemin-requiring mutants were isolated from haemin-permeable mutants. According to their growth responses to haem precursors and their patterns of porphyrin accumulation, the 55 mutants fell into three groups which were judged to have defects in 5-aminolaevulinate dehydratase, ferrochelatase, and uroporphyrinogen III cosynthase or uroporphyrinogen decarboxylase. In mutants of the group deficient in 5-aminolaevulinate dehydratase, the mutations were adjacent to lac, and evidence is presented that the mutations were in hemB and were commonly deletions extending into proC.
mesh_terms: D000622:Aminolevulinic Acid / Q000378:metabolism; D002874:Chromosome Mapping; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D006418:Heme / Q000031:analogs & derivatives*; D006427:Hemin / Q000378:metabolism*; D011163:Hydroxymethylbilane Synthase / Q000378:metabolism; D009154:Mutation; D000623:Porphobilinogen Synthase / Q000378:metabolism; D011166:Porphyrins / Q000096:biosynthesis
chemical_list: D011166:Porphyrins; D006418:Heme; D006427:Hemin; D000622:Aminolevulinic Acid; D011163:Hydroxymethylbilane Synthase; D000623:Porphobilinogen Synthase