Abstract
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).
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
