Polyphosphates, synthesis

These ideas are readily testable and therefore can constitute a research enterprise. For example, the hydrolysis of polyphosphates to monomeric phosphate is relatively fast in weak aqueous acid and warm temperatures. [129, 205] Curiously, however, the same acidity would promote thermal polyphosphate synthesis under the dehydrating conditions of the heated subterranean mineral pores within a hydrothermal system. Measurement of the stability of polyphosphates in microscopic environments where the activity of water might be low would test the phosphate-polyphosphate conjecture made above. If polyphosphates are not stabilized relative to bulk water solutions, as dissolved within micron-sized mineral pores or within vesicles, perhaps in the presence of dissolved organics, then this hypothesis is in danger. Additionally, the proposed production and delivery of polyphosphates by hydrothermal systems can be tested in an appropriate laboratory setting. 

ATP -I- (phosphate)n = ADP -h (phosphate)rn-i (<12> mechanism [10] <12> short chain polyphosphates are incorporated at the ends of the long chain product [9] <12> both polyphosphate synthesis and polyphosphate utilization follow a processive mechanism [10])... 

PPK-2 is believed to act primarily in the direction of GTP and ATP synthesis, and PPK-1 in the direction of polyphosphate synthesis. PPK-1 and PPK-2 are present in a wide variety of prokaryotes, including many pathogenic bacteria... 

No gene in yeast encodes a PPK-like protein, but four genes—unrelated to bacterial PPKgenes—are necessary for the synthesis of polyphosphate. The mechanism for polyphosphate synthesis in eukaryotes seems to be quite different from that in prokaryotes. 

S. J. Ferguson, D. G. Gadian, R. Glynn and G. Schulman (1978). Evidence from 31P nuclear magnetic resonance that polyphosphate synthesis is a slip reaction in Paracoccus denitrificans. Biochem. Soc. Trans., 1, 176-179. 

C. R. Tinsley and E. C. Gotschlich (1995). Cloning and characterization of the meningococcal polyphosphate kinase gene production of polyphosphate synthesis mutant. Infect. Immun., 63, 1624-1630. 

Seeds, A.M., Sandquist, J.C., Spana, E.P., and York, J.D., 2004, A molecular basis for inositol polyphosphate synthesis in Drosophila melanogaster. J. Biol. Chem. 279 47222-47232. 

In the budding yeast, inositol polyphosphate synthesis proceeds via what is likely to be one of the earliest incarnations of a PLC-dependent pathway for higher inositol polyphosphate metabolism in eukaryotes. Early biochemical studies in yeast (and plants) failed to identify a calcium-sensitive Ins(l,4,5)P3 3-kinase activity analogous to that found in mammalian cells. Instead, these studies identified C6-hydroxyl phosphorylation of Ins(l,4,5)P3 and formation of Ins(l,4,5,6)P4 as the most likely first anabolic step in the production of higher inositol polyphosphates (22). Additional biochemical studies identified the sequential phosphorylation of Ins(l,4,5,6)P4 to Ins(l,3,4,5,6)P5 followed by Ins(l,2,3,4,5,6)P6 (23). These findings were interpreted as proof of the existence of disparate pathways in yeast and mammals for the metabolism and functionality of Ins(l,4,5)P3. In contrast, the eventual cloning of the yeast Ins(l,4,5)P3 kinase activity found that mammalian and yeast inositol metabolism were more closely related than initially suspected. 

Polyphosphate can replace ATP in the phosphorylation of glucose in numerous microorganisms [23,24]. Since the equilibrium of Reaction (1) is on the side of polyphosphate synthesis, this enzyme is not employed in polyphosphate degradation. Instead, a poly-P AMP phosphotransferase activity was found in cell-free extracts of the phosphate-accumulating bacterium Acinetobacter johnsonii which catalyzes Reaction (2)... 

Kulaev (1979) showed that such evolutionary conserved organisms as Micrococcus lysodeicticus and P. shermanii possess a glycolysis-dependent polyphosphate synthesis system in addition to the ATP-dependent one. It has been established (Bobic, 1971 Kulaev et al, 1973) that the biosynthesis of polyphosphates in propionibacteria can proceed both via the terminal phosphate of ATP as well as that of 1,3-diphosphoglyceric acid (1,3-DPGA) ... 

Todd, A R. (1957) Newer methods of polyphosphate synthesis, in phosphoric esters and related compounds Chem. Soc. (Lond.) Spec. Publ. No. 8, 91-98 and references therein cited. 

---