Isolation and characterization of a Saccharomyces cerevisiae mutant with impaired glutamate synthase activity.
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.
Folch
J L
JL
Departamento de Biología Molecular de Plantas, UNAM, Cuernavaca, Morelos.
Antaramián
A
A
Rodríguez
L
L
Bravo
A
A
Brunner
A
A
González
A
A
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*
D005970:Glutamate Synthase; D005969:Glutamate Dehydrogenase; D000637:Transaminases