Inositol-1-phosphate

Inositol Phosphates Their Chemistry, Biochemistry and Physiology, by D.J. Cosgrove... 

Phosphate esters and anhydrides dominate the living world. Major areas of synthetic interest include oligonucleotides (polymeric phosphate diesters), phospho-rylated peptides, phospholipids, glycosyl phosphates, and inositol phosphates. ... 

Increase in inositol phosphates and cytosolic [Ca2+] Activation of MAPK pathway NN SR 142948A ... 

Human Stably transfected CHO cells Increase in inositol phosphates, cytosolic [Ca2+], arachidonic acid activation of MAPK pathway SR 48692 NT ... 

A. Inositol Phosphates.—Phosphatidyl inositol (71) is hydrolysed in mammalian tissues to wyo-inositol 1,2-cyclic phosphate (72).i myoinositol 1-phosphate (73) is released simultaneously but is not converted into (72) by the enzyme system. Periodate oxidation of (73) liberates orthophosphate quantitatively, the unstable dialdehyde phosphate (74) being an intermediate. Little or no orthophosphate is released from glucose 6-phosphate under the same oxidative conditions, and this reaction has been used to assay (73). 

The simultaneous analysis of orthophosphate, glycerol phosphates, and inositol phosphates has been achieved by spectrophotometric analysis of the molybdovanadate complexes. Also, a sensitive and selective chemiluminescent molecular emission method for the estimation of phosphorus and sulphur is described, which is based on passing solutions into a cool, reducing, nitrogen-hydrogen diffusion flame. For organic compounds it was usually necessary to prepare test solutions by an oxygen-flask combustion technique. 

Paper chromatography of inositol phosphates obtained from soil extracts is described. ... 

SHAMSUDDIN A M (1995) Inositol phosphates have novel anti-cancer function ". J Nutr, 125 Supplement 725S-732S. 

Rounds, M.A. and Nielsen, S. S., Anion-exchange high-performance liquid chromatography with post-column detection for the analysis of phytic acid and other inositol phosphates, /. Chromatogr. A, 653, 148, 1993. 

Franz, H., Maier, H. G., Inositol phosphates in coffee and related beverages. Part 2. Coffee. Dtsch. Lebensm.-Rundsch. 9(5), 345, 1994. (in German) (CA123 31752j)... 

Mobilization of Ca2+ from intracellular pools can be achieved with 2,5-di(tert-butyl)-l,4-benzohydroquinone (tBuBHQ), an agent that elevates intracellular levels of Ca2+ by mobilizing the inositol 1,4,5-triphosphate-sensitive Ca2+ pool without increasing inositol phosphate itself [220], Llopis et al. [204] showed... 

In addition to terpenes (as described above), carbohydrates have also been used as substrates in domino metathesis reactions, the aim being to synthesize enan-tiopure polyhydroxylated carbocyclic rings. These structures are components of several biologically active compounds such as aminoglycoside antibiotics [254], inositol phosphates [255], and carbanucleosides [256]. An efficient entry to this skeleton was developed by Madsen s group using a domino RCM/CM of the carbohy-... 

A bacterial phosphatidylinositol specific phospholipase C (PI-PLC) had been available for many years before it was demonstrated to strip a number of membrane-bound proteins from eukaryotic cell surfaces [1], Such proteins are anchored by a PI moiety in which the 6 position of inositol is glycosidically linked to glucosamine, which in turn is bonded to a polymannan backbone (Fig. 3-10). The polysaccharide chain is joined to the carboxyl terminal of the anchored protein via amide linkage to ethanolamine phosphate. The presence of a free NH2 group in the glucosamine residue makes the structure labile to nitrous acid. Bacterial PI-PLC hydrolyzes the bond between DAG and phosphati-dylinositols, releasing the water-soluble protein polysac charide-inositol phosphate moiety. These proteins are tethered by glycosylphosphatidylinositol (GPI) anchors. 

The metabolism of inositol phosphates leads to regeneration of free inositol 354... 

The inositol polyphosphate 5-phosphatases belong to a family of enzymes that terminate the signals generated by inositol lipid kinases and PLC. To date, two major types of 5-phosphatase have been identified, both of which share a common 5-phosphatase domain of approximately 300 amino acids, with several highly conserved motifs. Type-I enzymes are 43-65 kDa and preferentially hydrolyze 1(1,4,5)P3 and 1(1,3,4,5)P4, with the attendant formation of I(1,4)P2 and 1(1,3,4)P3, but have little or no activity towards membrane-bound phosphoinositides. The pro-totypic form of a type-15-phosphatase is a 43 kDa protein that is post-translationally modified by farnesylation of the carboxyl terminus CAAX motif this modification juxtaposes the enzyme with the membrane. Type-II enzymes are larger (75-160 kDa) and will hydrolyze both water-soluble inositol phosphates and lipids that... 

FIGURE 20-7 Pathways of inositol phosphate metabolism. Note that the metabolism of the second messenger I(1,4,5)P3 is shown to the left of the dashed line, while the interconversions of the higher inositol phosphates are shown to the right of the dashed line. Only the quantitatively major established pathways are depicted. Li+ is known to block the dephosphorylation reactions indicated by the (black) bars. Numbers refer to the following enzymes 1, inositol polyphosphate 5-phosphatase (I) 2, inositol polyphosphate 1-phosphatase 3,I(1,4,5)P3 3-kinase 4, inositol polyphosphate 4-phosphatase 5, inositol polyphosphate 3-phosphatase 6, inositol monophosphate phosphatase 7, I(1,3,4)P3 6-kinase/I(3,4,5,6)P4 1-kinase 8, Ipmk 9, DIPP 10, IP6 kinase 11, Ipk 1 12, MIPP 13, PP-IP5 kinase. 

The action of Li+ on inositol monophosphatase has greatly facilitated the use of [3H] inositol in the study of stimulated phosphoinositide turnover [19]. Berridge and colleagues demonstrated that in the presence of both Li+ and a phosphoinositide-linked ligand, the amount of labeled intracellular inositol phosphates that accumulates... 

Fisher, S. K., Novak, J. E. and Agranoff, B. W. Inositol and higher inositol phosphates in neural tissues homeostasis, metabolism and functional significance. J. Neurochem. 82 736-754, 2002. 

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