RESUMO
Saccharomyces cerevisiae mutants acidifying glucose medium containing bromocresol purple were shown to excrete protons when placed in unbuffered water in the absence of any external carbon source. The mutants belong to 16 different complementation groups. Most of them do not grow on glycerol and the excreted protons are associated to particular sets of organic anions such as citrate, aconitate, succinate, fumarate or malate. These novel types of respiratory mutations seem to be located in genes operating in the Krebs or glyoxylate cycle.
Assuntos
Ácidos/metabolismo , Mutação , Saccharomyces cerevisiae/classificação , Saccharomyces cerevisiae/metabolismo , Água/metabolismo , Ciclo do Ácido Cítrico/fisiologia , Concentração de Íons de Hidrogênio , Oxirredução , Prótons , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimentoRESUMO
We present the results of genetical and biochemical investigations of yeast mutants which presumably are deficient in different steps of the Krebs cycle. The investigation of the activities of the Krebs cycle enzymes suggests that we have isolated two types of mutants: structural and regulatory.
