The major nonmitochondrial isozyme of malate dehydrogenase (MDH2) in Saccharomyces cerevisiae cells grown with acetate as a carbon source was purified and shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to have a subunit molecular weight of approximately 42,000. Enzyme assays and an antiserum prepared against the purified protein were used to screen a collection of acetate-nonutilizing (acetate-) yeast mutants, resulting in identification of mutants in one complementation group that lack active or immunoreactive MDH2. Transformation and complementation of the acetate- growth phenotype was used to isolate a plasmid carrying the MDH2 gene from a yeast genomic DNA library. The amino acid sequence derived from complete nucleotide sequence analysis of the isolated gene was found to be extremely similar (49% residue identity) to that of yeast mitochondrial malate dehydrogenase (molecular weight, 33,500) despite the difference in sizes of the two proteins. Disruption of the MDH2 gene in a haploid yeast strain produced a mutant unable to grow on minimal medium with acetate or ethanol as a carbon source. Disruption of the MDH2 gene in a haploid strain also containing a disruption in the chromosomal MDH1 gene encoding the mitochondrial isozyme produced a strain unable to grow with acetate but capable of growth on rich medium with glycerol as a carbon source. The detection of residual malate dehydrogenase activity in the latter strain confirmed the existence of at least three isozymes in yeast cells.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|