Related Experiment Videos
H+/K+ exchange in reconstituted yeast plasma membrane vesicles
J Ramírez1, A Peña, M Montero-Lomelí
1Department of Microbiology, Universidad Nacional Autónoma de México, Mexico.
Biochimica Et Biophysica Acta
|December 4, 1996
Summary
Researchers identified a yeast plasma membrane H+/K+ exchange system that regulates internal pH. This system exchanges protons for potassium ions and is inhibited by amiloride.
Area of Science:
- Biochemistry
- Cell Biology
- Membrane Transport
Background:
- Yeast plasma membrane harbors transport systems crucial for cellular homeostasis.
- Understanding ion exchange mechanisms is vital for cellular pH regulation.
Purpose of the Study:
- To investigate a potential proton (H+) / potassium (K+) exchange system in yeast plasma membranes.
- To characterize the properties and selectivity of this putative exchange system.
Main Methods:
- Utilized pyranine-loaded yeast plasma membrane vesicles to monitor internal pH via fluorescence.
- Assessed the effect of monovalent cations on internal pH and characterized system inhibition and selectivity.
Main Results:
- Monovalent cation addition increased internal vesicle pH, indicating H+ efflux.
- The system exhibited partial selectivity for K+ over other cations and was inhibited by amiloride.
- Activity was dependent on yeast plasma membrane presence and pH gradients, with low cation affinity.
Conclusions:
- A novel H+/K+ exchange system exists in the yeast plasma membrane, distinct from mitochondrial systems.
- This system likely plays a role in regulating intracellular pH during high potassium (K+) accumulation in yeast cells.