Abstract
The influence of extracellular concentration of orthophosphate on the phosphate‐fractions has been investigated in phosphate starved cells of Candida utilis. In consequence of phosphate starvation an intensive binding of orthophosphate and synthesis of inorganic polyphosphate occurs. These two components are the most important parts of the cells capacity for phosphate‐uptake.
The extracellular concentration of orthophosphate does not effect the patterns of intracellular phosphate compounds directly. The same effects could be observed with constant cellmass and different phosphate concentrations or constant phosphate concentrations and different cellmass. The most rapid part of the uptake process (orthophosphate saturation of the cells) could be observed best using high cell dry weight (= high uptake capacity) and low phosphate concentrations. The main effect of phosphate uptake at higher ratios of \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{{\rm extracellular phosphate}}}{{{\rm cell dry weight}}} $\end{document} is the formation of inorganic polyphosphosphate, while the orthophosphate‐pool remains almost constant. Glucose decreases the orthophosphate‐pool and increases the TCA‐soluble phosphate compounds even in subsequent phosphate uptake.