Ammonium toxicity and potassium limitation in yeast

David C. Hess, Wenyun Lu, Joshua D. Rabinowitz, David Botstein

Research output: Contribution to journalArticlepeer-review

123 Scopus citations


DNA microarray analysis of gene expression in steady-state chemostat cultures limited for potassium revealed a surprising connection between potassium and ammonium: potassium limits growth only when ammonium is the nitrogen source. Under potassium limitation, ammonium appears to be toxic for Saccharomyces cerevisiae. This ammonium toxicity, which appears to occur by leakage of ammonium through potassium channels, is recapitulated under high-potassium conditions by over-expression of ammonium transporters. Although ammonium toxicity is well established in metazoans, it has never been reported for yeast. To characterize the response to ammonium toxicity, we examined the filtrates of these cultures for compounds whose excretion might serve to detoxify the ammonium (such as urea in mammals). Using liquid chromatography-tandem mass spectrometry to assay for a wide array of metabolites, we detected excreted amino acids. The amounts of amino acids excreted increased in relation to the severity of growth impairment by ammonium, suggesting that amino acid excretion is used by yeast for ammonium detoxification.

Original languageEnglish (US)
Pages (from-to)2012-2023
Number of pages12
JournalPLoS biology
Issue number11
StatePublished - Nov 2006

All Science Journal Classification (ASJC) codes

  • General Agricultural and Biological Sciences
  • General Biochemistry, Genetics and Molecular Biology
  • General Immunology and Microbiology
  • General Neuroscience


Dive into the research topics of 'Ammonium toxicity and potassium limitation in yeast'. Together they form a unique fingerprint.

Cite this