The Regulation of Intracellular Orthophosphate Concentration

Abstract

Even though the intracellular concentration of orthophosphate (Pi) is an important influence on intracellular metabolism, its regulation is not well understood. In this paper a simple model is used to explain how cellular [Pi] is influenced by the transmembrane electrical potential and sodium distribution and by the kinetic properties of active and passive Pi transport, and how these factors affect the dependence of cellular [Pi] on extracellular [Pi] and its response to small displacements from equilibrium. Parts of the analysis are also applicable to other transported metabolites.