title: Isolation and characterization of a Saccharomyces cerevisiae mutant with impaired glutamate synthase activity.
abstract: A mutant of Saccharomyces cerevisiae that lacks glutamate synthase (GOGAT) activity has been isolated. This mutant was obtained after chemical mutagenesis of a NADP-glutamate dehydrogenase-less mutant strain. The gdh gus mutant is a glutamate auxotroph. The genetic analysis of the gus mutant showed that the GOGAT-less phenotype is due to the presence of two loosely linked mutations. Evidence is presented which suggests the possibility that S. cerevisiae has two GOGAT activities, designated GOGAT A and GOGAT B. These activities can be distinguished by their pH optima and by their regulation by glutamate. Furthermore, one of the mutations responsible for the GOGAT-less phenotype affected GOGAT A activity, while the other mutation affected GOGAT B activity.
authors.affiliation: Departamento de Biología Molecular de Plantas, UNAM, Cuernavaca, Morelos.
authors.forename: J L
authors.initials: JL
authors.lastname: Folch
authors.forename: A
authors.initials: A
authors.lastname: Antaramián
authors.forename: L
authors.initials: L
authors.lastname: Rodríguez
authors.forename: A
authors.initials: A
authors.lastname: Bravo
authors.forename: A
authors.initials: A
authors.lastname: Brunner
authors.forename: A
authors.initials: A
authors.lastname: González
mesh_terms: D003433:Crosses, Genetic; D005800:Genes, Fungal; D005838:Genotype; D005969:Glutamate Dehydrogenase / Q000378:metabolism; D005970:Glutamate Synthase / Q000235:genetics* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009154:Mutation; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D000637:Transaminases / Q000235:genetics*
chemical_list: D005970:Glutamate Synthase; D005969:Glutamate Dehydrogenase; D000637:Transaminases