ISSN:
0749-503X
Keywords:
Yeast
;
vacuole
;
H+-ATPase
;
guanosine
;
organic acids transport
;
Ca2+-modulation
;
Life and Medical Sciences
;
Genetics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
Isolated vacuoles of the yeast Saccharomyces pastorianus accumulate citrate, α-ketoglutarate, malate and guanosine. This accumulation is Mg ATP-dependent and inhibited by protonophores. The ionophores monensin and A23187 (electroneutral Men+/nH+-exchange) inhibit guanosine accumulation but fail to block citrate uptake. Mg2+ ions (2 mM) increase the values of both Δ\documentclass{article}\pagestyle{empty}\begin{document}$ \tilde \mu $\end{document}H+ components and stimulate the uptake of all the above compounds. Ca2+ ions (1 mM), hyperpolarizing the yeast vacuolar membrane and dissipating the pH gradient, inhibit guanosine uptake and stimulate that of citrate. It is concluded that guanosine is transported into yeast vacuoles by an H+/guanosine antiporter while citrate, malate and α-ketoglutarate are translocated by a uniporter(s) at the expense of the membrane potential (positive inside).
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/yea.320070509
