Inositol phosphates synthesis

Raboy,V, and Gerbasi, P., 1996, Genetics of myo-inositol phosphate synthesis and accumulation. In Biswas, B.B., Biswas, S. (eds.), mw-Inositol Phosphates, Phosphoinositides, and Signal Transduction. Plenum Press, New York, pp. 257-285. 

Li+ causes malformation and affects regeneration in some protozoans, for example Tetrahymenapyriformis [231], by inhibiting both DNA and RNA synthesis by affecting regeneration in Hydra [232], planarians [233], and annelids [234] and by affecting cell signaling mediated by both inositol phosphate metabolism [235] and adenylate cyclase [236] in slime molds. 

In summary, the release of nenrotransmitter from a presynaptic neurone into a synaptic cleft occurs via the process of exocytosis, which is regulated by the increase in Ca " ion concentration in the presynaptic terminal. The increase in Ca " ion concentration is achieved by release of Ca " ions by opening of the Ca ion channel in the endoplasmic reticulum, which is controlled by the concentration of IP3. Failure to release inositol from the inositol phosphates reduces the free inositol concentration, which interferes in the synthesis of PIP2. The phospholipase no longer catalyses a zero order reaction. Consequently, sufficient IP3 to activate the ion channel is released in the presynaptic neurone, so that less nenrotransmitter is released into the synaptic cleft (Figure 12.19). 

Figure 11-9 Scheme showing synthesis and release of diacylglycerol and inositol phosphates and their regulation of calcium concentration in response to hormonal stimulation. 

S. V. Ley, Stereoselective synthesis of inositol phosphates, Pure Appl. Chem. 1990, 62, 2031-2034. 

Reitz, A. B. (1991) Inositol Phosphates and Derivatives, Synthesis, Biochemistry and Therapeutic Potential, ACS Symposia Series, Washington, D.C. 

For reviews concerning the protection and synthesis of phosphates in oligonucleotides and inositol phosphates, see the list of reviews at the end of chapter 1. 

Parthasarathy, R., and Eisenberg, F., Jr., 1990, Biochemistry, stereochemistry, and nomenclature of the inositol phosphates, In Reitz, A.B. (ed.), Inositol Phosphates and Derivatives Synthesis, Biochemistry, and Therapeutic Potential. ACS Symposium Series 463. American Chemical Society, Washington, DC, pp. 1-19. 

Finally, new studies often illuminate the importance of pathways and metabolites that simply were not initially observed in first-generation studies. A great example of this is the study of Martin et al. (2000) which showed that the Ins phosphate pathways in the amoeba Entamoeba histolytic in fact use neo-inositol and not ///vd-inositol as the backbone for Ins phosphate synthesis. This suggests that a reanalysis of basic assumptions, leading to a new synthesis of the nature and role of these pathways, might be achieved in the coming years. 

Plant foods contain relatively large amounts of inositol phosphates, including the hexaphosphate, phytic acid. Phytate chelates minerals, such as calcium, zinc, and magnesium, forming insoluble complexes that are not absorbed. However, both intestinal phosphatases and endogenous phosphatases (phytase) in many foods dephosphorylate a significant proportion of dietary phytate. The inositol released can be absorbed and utilized for phosphatidylinositol synthesis. 

Auesukaree C, Tochio H, Shirakawa M, Kaneko Y, Harashima S. Plclp, Arg82p, and Kcslp, enzymes involved in inositol pyrophosphate synthesis, are essential for phosphate regulation and polyphosphate accumulation in Saccharomyces cerevisiae. J. Biol. Chem. 2005 280 25127-25133. 

The mode of action is not fully understood. The main effect of lithium is probably to inhibit hydrolysis of inositol phosphate, so reducing the recycling of free inositol for synthesis of phosphatidylino-... 

This protocol can be applied to the 6-0-acetyl-5-enopyranoside 229 with good efficiency and the utility is well demonstrated by the synthesis of the D-myo-inositol phosphate, IP3 [193,194],... 

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