Inorganic polyphosphate functions at various stages of cell evolution

An important property of all chemical components of the living cells is their polyfunctionality. However, the complex of their functions may significantly change in the process of evolution. This can be well illustrated by the example of polyphosphates. In procaryotes, polyphosphates are involved in many biochemical and physiological processes and their metabolic regulation. Their metabolism is first closely connected with adenyl metabolism and bioenergetics. In the lower eucaryotes, the cells of which are evidently of endosymbiotic origin, polyphosphate metabolism of various organelles is considerably different and closely connected with the specificity of their function. In these organisms, polyphosphates are involved in metabolic and probably in genetic regulation of phosphate and adenyl metabolism. However, they first play the role of an osmotically inert reserve of inorganic phosphorus. In the higher animals having the hormonal and nervous systems of cell metabolism regulation, the function of polyphosphates as a metabolic regulator disappears. However, they apparently still function as regulators of gene expression and some transport processes. © 1995 Kluwer Academic Publishers.