title: Biosynthesis of sulphur amoni acids in Saccharomyces cerevisiae. I. Genetic analysis of leaky mutants of sulphite reductase.
abstract: The hypothesis of an alternative pathway of sulphur amino acid synthesis as the basis of the prototrophy of sulphite reductase negative (Sr--) strains of Saccharomyces cerevisiae has been rejected. Met- mutants obtained after phenylmercuric nitrate treatment of Sr- strains accumulate H2S as the consequence of a metabolic block which leads to methionine auxotrophy. This mutation has been shown to be independent of the Sr locus. We assume that the molecular basis of the prototrophy of Sr- mutant resides in a leaky missense induced in the Sr gene.
mesh_terms: D000603:Amino Acids, Sulfur / Q000096:biosynthesis*; D002470:Cell Survival / Q000187:drug effects; D003433:Crosses, Genetic; D005821:Genetic Techniques; D006862:Hydrogen Sulfide / Q000378:metabolism; D008628:Mercury / Q000494:pharmacology; D008715:Methionine / Q000378:metabolism; D009154:Mutation / Q000187:drug effects; D009942:Organometallic Compounds / Q000494:pharmacology; D010088:Oxidoreductases / Q000378:metabolism*; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013447:Sulfites; D013458:Sulfur Dioxide / Q000378:metabolism
chemical_list: D000603:Amino Acids, Sulfur; D009942:Organometallic Compounds; D013447:Sulfites; D013458:Sulfur Dioxide; D008715:Methionine; D010088:Oxidoreductases; D008628:Mercury; D006862:Hydrogen Sulfide