- Regioselective opening of myo-inositol orthoesters: Mechanism and synthetic utility
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Acid hydrolysis of myo-inositol 1,3,5-orthoesters, apart from orthoformates, exclusively affords the corresponding 2-O-acyl myo-inositol products via a 1,2-bridged five-membered ring dioxolanylium ion intermediate observed by NMR spectroscopy. These C-2-substituted inositol derivatives provide valuable precursors for rapid and highly efficient routes to 2-O-acyl inositol 1,3,4,5,6-pentakisphosphates and myo-inositol 1,3,4,5,6-pentakisphosphate with biologically interesting and anticancer properties. Deuterium incorporation into the α-methylene group of such alkyl ester products (2-O-C(O)CD 2R), when the analogous alkyl orthoester is treated with deuterated acid, is established utilizing the novel orthoester myo-inositol 1,3,5-orthobutyrate as an example. Such deuterated ester products provide intermediates for deuterium-labeled synthetic analogues. Investigation into this selective formation of 2-O-ester products and the deuterium incorporation is presented with proposed mechanisms from NMR experiments.
- Godage, Himali Y.,Riley, Andrew M.,Woodman, Timothy J.,Thomas, Mark P.,Mahon, Mary F.,Potter, Barry V. L.
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p. 2275 - 2288
(2013/04/24)
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- Quantitative analysis of phytate globoids isolated from wheat bran and characterization of their sequential dephosphorylation by wheat phytase
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Wheat phytase was purified to investigate the action of the enzyme toward its pure substrate (phytic acid - myo-inositol hexakisphosphate) and its naturally occurring substrate (phytate globoids). Phytate globoids were purified to homogeneity from wheat bran, and their nutritionally relevant parameters were quantified by ICP-MS. The main components of the globoids were phytic acid (40% w/w), protein (46% w/w), and several minerals, in particular, K > Mg > Ca > Fe (in concentration order). Investigation of enzyme kinetics revealed that Km and Vmax decreased by 29 and 37%, respectively, when pure phytic acid was replaced with phytate globoids as substrate. Time course degradation of phytic acid or phytate globoids using purified wheat phytase was followed by HPIC identification of inositol phosphates appearing and disappearing as products. In both cases, enzymatic degradation initiated at both the 3- and 6-positions of phytic acid and end products were inositol and phosphate.
- Bohn, Lisbeth,Josefsen, Lone,Meyer, Anne S.,Rasmussen, Soren K.
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p. 7547 - 7552
(2008/09/19)
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- Flexible stereo- and regioselective synthesis of myo-inositol phosphates (part 1): Via symmetrical conduritol B derivatives
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A practical route is described for the preparation of myo-inositol polyphosphates. Optically pure myo-inositol derivatives can be prepared from p-benzoquinone in both forms by enzymatic resolution of a C2- symmetric diacetoxyconduritol B key in
- Podeschwa, Michael A. L.,Plettenburg, Oliver,Altenbach, Hans-Josef
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p. 3101 - 3115
(2007/10/03)
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- The pathway of dephosphorylation of myo-inositol hexakisphosphate by phytases from wheat bran of Triticum aestivum L. cv. Nourin #61
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Phytases are the primary enzymes responsible for the hydrolysis of phytic acid, myo-inositol-1, 2, 3, 4, 5, 6-hexakisphosphate (InsP6). The pathway of hydrolysis of InsP6 by phytase from wheat bran of Triticum aestivum L. cv. Nourin #61 is proved in this study. Structures of the intermediates were established by a variety of nuclear magnetic resonance techniques (1H-, two-dimensional 1H-1H coupling-correlation spectra and two-dimensional 31P-1H correlation spectra), gas chromatography, and bioassay. On the basis of the structures identified, initial hydrolysis of the phosphate ester occurs at the D/L-4 position of InsP6 to yield D/L-Ins (1, 2, 3, 5, 6) P5. After the dephosphorylation, the pathway of dephosphorylation is divided into two routes. The main route proceeds via D/L-Ins (1, 2, 5, 6) P4, D/L-Ins (1, 2, 6) P3 and D/L-Ins (1, 2) P2, while the minor route proceeds via D/L-Ins (1, 2, 3, 6) P4, Ins (1, 2, 3) P3 and D/L-Ins (1, 2) P2. D/L-Ins (1, 2) P2 is hydrolyzed at the D/L-1 or 2-position, and finally myo-inositol is produced.
- Nakano, Tadao,Joh, Toshio,Narita, Kazumasa,Hayakawa, Toshiro
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p. 995 - 1003
(2007/10/03)
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- Synthesis of 2-substituted myo-inositol 1,3,4,5-tetrakis(phosphate) and 1,3,4,5,6-pentakis(phosphate) analogs
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Some biologically interesting inositol poly(phosphate) derivatives, 2-O-(P-aminobenzoyl)-myo-inositol 1,3,4,5-tetrakis(phosphate), 2-O-(4-aminocyclohexylcarbonyl)-myo-inositol 1,3,4,5-tetrakis(phosphate), myo-inositol 1,3,4,5,6-pentakis(phosphate), and its 2-substituted analogs, were synthesized. Inositol tetrakis(phosphate) and pentakis(phosphate) affinity columns were also prepared. The inositol 1,3,4,5-tetrakis(phosphate) affinity column was found to be effective in isolating the binding proteins from bovine cardiac membranes.
- Ozaki,Koga,Ling,Watanabe,Kimura,Hirata
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p. 1058 - 1063
(2007/10/02)
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