title: Isolation of a trans-dominant histidase-negative mutant of Salmonella typhimurium.
abstract: A mutation of Salmonella typhimurium was obtained that results in the failure of cells to synthesize the enzyme l-histidine ammonia-lyase (histidase). The mutation mapped within the hutH gene and in merodiploid strains was dominant over the wild-type allele. Extracts from cells bearing the trans-dominant histidase-negative allele were shown to contain material that reacts immunologically with antiserum against purified wild-type histidase. It is proposed that the trans-dominant allele results in the synthesis of defective histidase subunits that can combine with, and partially inactivate, wild-type histidase subunits. This subunit mixing presumably does occur, as the enzyme synthesized in a hybrid merodiploid strain is abnormally heat sensitive.
mesh_terms: D000483:Alleles; D000642:Ammonia-Lyases / Q000096:biosynthesis*; D000645:Ammonium Sulfate; D000818:Animals; D002021:Buffers; D002499:Centrifugation, Density Gradient; D002845:Chromatography; D002848:Chromatography, DEAE-Cellulose; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D003470:Culture Media; D003851:Deoxyribonucleases; D006638:Histidine Ammonia-Lyase / Q000032:analysis / Q000096:biosynthesis* / Q000276:immunology; D006358:Hot Temperature; D009154:Mutation; D011817:Rabbits / Q000276:immunology; D012413:Rubidium; D012483:Salmonella Phages; D012486:Salmonella typhimurium / Q000201:enzymology* / Q000254:growth & development / Q000276:immunology / Q000302:isolation & purification; D014559:Urocanate Hydratase / Q000032:analysis
chemical_list: D002021:Buffers; D003470:Culture Media; D003851:Deoxyribonucleases; D014559:Urocanate Hydratase; D000642:Ammonia-Lyases; D006638:Histidine Ammonia-Lyase; D012413:Rubidium; D000645:Ammonium Sulfate