The concentration of ammonia regulates nitrogen metabolism in Saccharomyces cerevisiae.
Saccharomyces cerevisiae was grown in a continuous culture at a single dilution rate with input ammonia concentrations whose effects ranged from nitrogen limitation to nitrogen excess and glucose limitation. The rate of ammonia assimilation (in millimoles per gram of cells per hour) was approximately constant. Increased extracellular ammonia concentrations are correlated with increased intracellular glutamate and glutamine concentrations, increases in levels of NAD-dependent glutamate dehydrogenase activity and its mRNA (gene GDH2), and decreases in levels of NADPH-dependent glutamate dehydrogenase activity and its mRNA (gene GDH1), as well as decreases in the levels of mRNA for the amino acid permease-encoding genes GAP1 and PUT4. The governing factor of nitrogen metabolism might be the concentration of ammonia rather than its flux.
ter Schure
E G
EG
Department of Molecular Cell Biology, Utrecht University, The Netherlands.
Silljé
H H
HH
Verkleij
A J
AJ
Boonstra
J
J
Verrips
C T
CT
D026905:Amino Acid Transport Systems; D026921:Amino Acid Transport Systems, Neutral; D000641:Ammonia / Q000378:metabolism / Q000494:pharmacology*; D001483:Base Sequence; D018533:Biomass; D005656:Fungal Proteins / Q000235:genetics; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005969:Glutamate Dehydrogenase / Q000378:metabolism; D018086:Glutamate Dehydrogenase (NADP+) / Q000378:metabolism; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D018698:Glutamic Acid / Q000096:biosynthesis; D005973:Glutamine / Q000096:biosynthesis; D007656:Ketoglutaric Acids / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000378:metabolism*; D009994:Osmolar Concentration; D012331:RNA, Fungal / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*
D026905:Amino Acid Transport Systems; D026921:Amino Acid Transport Systems, Neutral; D005656:Fungal Proteins; D007656:Ketoglutaric Acids; D026901:Membrane Transport Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D005973:Glutamine; D018698:Glutamic Acid; D000641:Ammonia; C033082:proline transporter; D005969:Glutamate Dehydrogenase; D018086:Glutamate Dehydrogenase (NADP+); D005974:Glutamate-Ammonia Ligase; D009584:Nitrogen