Enzymes
| UniProtKB help_outline | 431 proteins |
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- Name help_outline 1D-myo-inositol hexakisphosphate Identifier CHEBI:58130 (Beilstein: 3886124) help_outline Charge -12 Formula C6H6O24P6 InChIKeyhelp_outline IMQLKJBTEOYOSI-GPIVLXJGSA-B SMILEShelp_outline [O-]P([O-])(=O)O[C@@H]1[C@H](OP([O-])([O-])=O)[C@H](OP([O-])([O-])=O)[C@@H](OP([O-])([O-])=O)[C@H](OP([O-])([O-])=O)[C@H]1OP([O-])([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 11 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H2O Identifier CHEBI:15377 (Beilstein: 3587155; CAS: 7732-18-5) help_outline Charge 0 Formula H2O InChIKeyhelp_outline XLYOFNOQVPJJNP-UHFFFAOYSA-N SMILEShelp_outline [H]O[H] 2D coordinates Mol file for the small molecule Search links Involved in 6,204 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline 1D-myo-inositol 1,2,3,5,6-pentakisphosphate Identifier CHEBI:58747 (Beilstein: 8035380) help_outline Charge -10 Formula C6H7O21P5 InChIKeyhelp_outline CTPQAXVNYGZUAJ-UOTPTPDRSA-D SMILEShelp_outline O[C@H]1[C@H](OP([O-])([O-])=O)[C@@H](OP([O-])([O-])=O)[C@H](OP([O-])([O-])=O)[C@H](OP([O-])([O-])=O)[C@@H]1OP([O-])([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 2 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline phosphate Identifier CHEBI:43474 Charge -2 Formula HO4P InChIKeyhelp_outline NBIIXXVUZAFLBC-UHFFFAOYSA-L SMILEShelp_outline OP([O-])([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 992 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:20960 | RHEA:20961 | RHEA:20962 | RHEA:20963 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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The structure of myo-inositol pentaphosphates.
Johnson L.F., Tate M.E.
Ann N Y Acad Sci 165:526-532(1969) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.
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Stable Isotopomers of myo-Inositol Uncover a Complex MINPP1-Dependent Inositol Phosphate Network.
Nguyen Trung M., Kieninger S., Fandi Z., Qiu D., Liu G., Mehendale N.K., Saiardi A., Jessen H., Keller B., Fiedler D.
The water-soluble inositol phosphates (InsPs) represent a functionally diverse group of small-molecule messengers involved in a myriad of cellular processes. Despite their centrality, our understanding of human InsP metabolism is incomplete because the available analytical toolset to characterize ... >> More
The water-soluble inositol phosphates (InsPs) represent a functionally diverse group of small-molecule messengers involved in a myriad of cellular processes. Despite their centrality, our understanding of human InsP metabolism is incomplete because the available analytical toolset to characterize and quantify InsPs in complex samples is limited. Here, we have synthesized and applied symmetrically and unsymmetrically <sup>13</sup>C-labeled <i>myo</i>-inositol and inositol phosphates. These probes were utilized in combination with nuclear magnetic resonance spectroscopy (NMR) and capillary electrophoresis mass spectrometry (CE-MS) to investigate InsP metabolism in human cells. The labeling strategy provided detailed structural information via NMR-down to individual enantiomers-which overcomes a crucial blind spot in the analysis of InsPs. We uncovered a novel branch of InsP dephosphorylation in human cells which is dependent on MINPP1, a phytase-like enzyme contributing to cellular homeostasis. Detailed characterization of MINPP1 activity in vitro and in cells showcased the unique reactivity of this phosphatase. Our results demonstrate that metabolic labeling with stable isotopomers in conjunction with NMR spectroscopy and CE-MS constitutes a powerful tool to annotate InsP networks in a variety of biological contexts. << Less
ACS Cent. Sci. 8:1683-1694(2022) [PubMed] [EuropePMC]
This publication is cited by 13 other entries.
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Myoinositol polyphosphate intermediates in the dephosphorylation of phytic acid by phytase.
TOMLINSON R.V., BALLOU C.E.
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Purification of an inositol (1,3,4,5)-tetrakisphosphate 3-phosphatase activity from rat liver and the evaluation of its substrate specificity.
Nogimori K., Hughes P.J., Glennon M.C., Hodgson M.E., Putney J.W. Jr., Shears S.B.
Hepatic inositol (1,3,4,5)-tetrakisphosphate 3-phosphatase activity was detected in a 100,000 x g soluble fraction and a detergent-solubilized particulate fraction. Activity in both fractions increased up to 40-fold after anion-exchange chromatography due to removal of endogenous inhibitors (Hodgs ... >> More
Hepatic inositol (1,3,4,5)-tetrakisphosphate 3-phosphatase activity was detected in a 100,000 x g soluble fraction and a detergent-solubilized particulate fraction. Activity in both fractions increased up to 40-fold after anion-exchange chromatography due to removal of endogenous inhibitors (Hodgson, M.E., and Shears, S.B. (1990) Biochem. J. 267, 831-834); at this stage the detergent-solubilized particulate activity comprised over 90% of total activity. The particulate phosphatase was further purified by affinity chromatography using heparin-agarose and red-agarose. The latter column resolved two peaks of enzyme activity (designated 1 and 2 by their order of elution from the column). Their proportions varied between experiments, but peak 2 generally predominated and so this was further purified by hydroxylapatite chromatography. The final preparation was typically 38,000-fold purified with a 7% yield. The apparent molecular mass of this enzyme was 66 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration. The enzyme had little or no affinity for the following: inositol (1,3,4,6)-tetrakisphosphate, inositol (1,3,4)-trisphosphate, inositol (1,3)-bisphosphate, inositol (3,4)-bisphosphate, and para-nitrophenylphosphate. At pH 7.4 the Km for inositol (1,3,4,5)-tetrakisphosphate was 130 nM and the Vmax was 4250 nmol/mg protein/min. The purified enzyme also dephosphorylated inositol (1,3,4,5,6)-pentakisphosphate to inositol (1,4,5,6)-tetrakisphosphate (Km = 40 nM, Vmax = 211 nmol/mg protein/min), and inositol hexakisphosphate to at least five isomers of inositol pentakisphosphate (Km = 0.3 nM, Vmax = 12 nmol/mg protein/min). The latter affinity is the highest yet defined for an enzyme involved in inositol phosphate metabolism. Determinations of IC50 values, and Dixon plots, revealed that with the (1,3,4,5)-tetrakisphosphate as substrate, the pentakis- and hexakisphosphates were potent competitive inhibitors; the Ki values (25 and 0.5 nM, respectively) were similar to their substrate Km values. The kinetic properties of this enzyme, as well as estimates of the cellular levels of its potential substrates, indicate that inositol pentakisphosphate and inositol hexakisphosphate are likely to be the preferred substrates in vivo. << Less
J. Biol. Chem. 266:16499-16506(1991) [PubMed] [EuropePMC]
This publication is cited by 3 other entries.
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The phytases. II. Properties of phytase fractions F 1 and F 2 from wheat bran and the myoinositol phosphates produced by fraction F 2 .
Lim P.E., Tate M.E.