GABA transport in Saccharomyces cerevisiae.
Gamma-aminobutyrate (GABA) accumulation in growing cultures of Saccharomyces cerevisiae was shown to occur by means of an active transport system that is inhibited by proton ionophores, azide, fluoride and arsenate ions. Transport occurred maximally at pH 5.0 and exhibited apparent Km values of 12 microM and 0.1 mM. Accumulated GABA did not efflux upon treatment with proton ionophores and exchanged with extracellular material only very slowly. However, release was complete upon treatment with nystatin. These observations raise the possibility that a major portion of intracellular GABA is sequestered in the vacuole. The response of GABA uptake to growth on various nitrogen sources suggested that uptake may be subject to several types of regulation.
Department of Microbiology and Immunology, University of Tennessee, Memphis 38163.
J
J
McKelvey
R
R
Rai
T G
TG
Cooper
D001693:Biological Transport, Active; D003470:Culture Media; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009584:Nitrogen / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D003470:Culture Media; D005680:gamma-Aminobutyric Acid; D009584:Nitrogen