Reversible permeability changes in the membrane of a yeast cell sugar compartment

Abstract

Sorbose uptake by Saccharomyces cerevisiae was increased 40 to 60% by glucose and other metabolizable sugars. Neither growth nor binding accounted for the increased uptake. However, accessibility of a restrictive intracellular compartment was increased as shown by counterflow and efflux measurements. Efflux from the compartment was more than doubled by glucose. This effect was reversed by washing and was prevented by iodoacetic acid and other inhibitors, but not by cycloheximide. No evidence was found for a facilitated transport system in the compartment membrane such as exists in the external cell membrane. It was concluded that sorbose crosses the compartment membrane by simple diffusion and that a reaction requiring the metabolism of sugars increases the permeability of the membrane. Arabinose and fucose entered and were lost from the compartment like sorbose, whereas dimethylsulfoxide was unaffected by the compartment. All three of these later compounds were bound by the cells when glucose was available in uptake suspensions. Binding was prevented by iodoacetic acid, but not by cycloheximide.

Intracellular ethanol — accumulation and exit from yeast and other cells

“…The equilibrium distribution coefficient of solutes into this water appears to be higher than that of the cytoplasmic water [75,76], mainly due to the contribution of the periplasmic space, and so whole cell coefficients are typically higher than the true cytoplasmic value. The equilibrium distribution of xylose into these same cells was only 0.87 [36], a result which has been confirmed by other workers [77]. The equilibrium distribution of xylose into these same cells was only 0.87 [36], a result which has been confirmed by other workers [77].…”

“…The following series of decreasing distribution coefficients have been reported [97]: L-sorbose > D-arabinose > Dlyxose > D-xylose,D-mannose = 1.0 > D-glucose > L-glucose > 2-deoxy-D-glucose > D-fructose >> Dgalactose > D-gulose > L-xylose > L-arabinose > D-ribose,D-fucose > L-rhamnose. However, the same distribution coefficients are observed in anaerobic grown cells [75,77] in which vacuolar material is virtually absent [100]. However, the same distribution coefficients are observed in anaerobic grown cells [75,77] in which vacuolar material is virtually absent [100].…”

Intracellular ethanol — accumulation and exit from yeast and other cells

“…For whole yeast cells values of the distribution coefficient of around 0.95 are common [36,38]. The equilibrium distribution of xylose into these same cells was only 0.87 [36], a result which has been confirmed by other workers [77]. The important significance of this difference will be discussed below.…”

“…Based upon the fact that the D-sugar always showed a higher distribution coefficient than the L-sugar, it was proposed that this distribution was the result of separate membrane enclosed compartments within the cell which accepted only certain kinds of sugars [96][97][98][99]. However, the same distribution coefficients are observed in anaerobic grown cells [75,77] in which vacuolar material is virtually absent [100]. The earlier hypothesis is therefore incorrect and the more simpler explanation based on the properties of the cytoplasm is more enlightening.…”

Physiological, biochemical, and mathematical studies of micro‐aerobic continuous ethanol fermentation by Saccharomyces cerevisiae. III: Mathematical model of cellular energetics and catabolism

“…(7), R 2 and R3 are functions of the ATP concentration only and are given by the catabolic model of the previous section. Equation (7) states that one mole of ethanol and one mole of glycerol production result in the phosphorylation and dephosphorylation respectively of one mole of ATP. A comparison of the data and the catabolic model prediction of Ratp is shown in Figure 6.…”