Energy‐Dependent Transport of Manganese into Yeast Cells and Distribution of Accumulated Ions

Abstract

Manganese transport into yeast cells is energy‐dependent. It is dependent on endogenous sources of energy and is inhibited by olygomycin (12.5–25 μg/ml), 2,4‐dinitrophenol (1 mM), 2‐deoxyglucose (1–50 mM) and sodium azide (1–10 mM), but is stimulated by cyanide and glucose. The stimulating effect of glucose is eliminated by N‐ethylmaleimide and iodoacetate, which apparently inhibit the transport of glucose itself. About 75% of the manganese accumulated in the presence of glucose is found in yeast protoplasts and nearly 25% in the cell walls. A major portion of the accumulated manganese is found in vacuoles. The concentration of osmotically free manganese in the cytosol did not exceed 2 mM, but the concentration in vacuoles was up to 14 mM. The tonoplast is assumed to have a transport system for divalent cations, thereby regulating their concentration in the cytosol. Copyright © 1977, Wiley Blackwell. All rights reserved