Enzymes
| UniProtKB help_outline | 1 proteins |
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Reaction participants Show >> << Hide
- Name help_outline myo-inositol Identifier CHEBI:17268 (Beilstein: 1907329; CAS: 87-89-8) help_outline Charge 0 Formula C6H12O6 InChIKeyhelp_outline CDAISMWEOUEBRE-GPIVLXJGSA-N SMILEShelp_outline O[C@H]1[C@H](O)[C@@H](O)[C@H](O)[C@H](O)[C@@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 25 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline S-adenosyl-L-methionine Identifier CHEBI:59789 Charge 1 Formula C15H23N6O5S InChIKeyhelp_outline MEFKEPWMEQBLKI-AIRLBKTGSA-O SMILEShelp_outline C[S+](CC[C@H]([NH3+])C([O-])=O)C[C@H]1O[C@H]([C@H](O)[C@@H]1O)n1cnc2c(N)ncnc12 2D coordinates Mol file for the small molecule Search links Involved in 868 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline 1D-4-O-methyl-myo-inositol Identifier CHEBI:18266 Charge 0 Formula C7H14O6 InChIKeyhelp_outline DSCFFEYYQKSRSV-GESKJZQWSA-N SMILEShelp_outline CO[C@@H]1[C@@H](O)[C@@H](O)[C@@H](O)[C@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 1 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,431 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline S-adenosyl-L-homocysteine Identifier CHEBI:57856 Charge 0 Formula C14H20N6O5S InChIKeyhelp_outline ZJUKTBDSGOFHSH-WFMPWKQPSA-N SMILEShelp_outline Nc1ncnc2n(cnc12)[C@@H]1O[C@H](CSCC[C@H]([NH3+])C([O-])=O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 792 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:23248 | RHEA:23249 | RHEA:23250 | RHEA:23251 | |
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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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Characterization of IMT1, myo-inositol O-methyltransferase, from Mesembryanthemum crystallinum.
Rammesmayer G., Pichorner H., Adams P., Jensen R.G., Bohnert H.J.
A full-length transcript, Imt1, encoding myo-inositol O-methyltransferase (EC 2.1.1.X) from the halophyte Mesembryanthemum crystallinum was expressed in Escherichia coli. The enzyme, IMT1, uses S-adenosyl-L-methionine to methylate myo-inositol to form D-ononitol. IMT1 with a monomeric mass of 41,0 ... >> More
A full-length transcript, Imt1, encoding myo-inositol O-methyltransferase (EC 2.1.1.X) from the halophyte Mesembryanthemum crystallinum was expressed in Escherichia coli. The enzyme, IMT1, uses S-adenosyl-L-methionine to methylate myo-inositol to form D-ononitol. IMT1 with a monomeric mass of 41,000 was isolated by ammonium sulfate fractionation, gel filtration and ion exchange chromatography to apparent purity on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The N-terminal amino acid sequence of the purified recombinant enzyme was identical to that encoded by the cDNA sequence. The apparent Km for S-adenosylmethionine was 0.18 mM with a Vmax of 1550 pkat/mg protein. The Km for myo-inositol was 1.32 mM. The reaction became substrate-inhibited by concentrations of S-adenosylmethionine greater than 0.5 mM. Inositol methyltransferase was competitively inhibited 50% with 0.01 mM S-adenosyl-homocysteine, while 1 mM homocysteine, homoserine, or adenosine did not inhibit. The enzyme exhibited a pH optimum of 7.8 and a temperature optimum of 37 degrees C. Activity of the isolated inositol methyltransferase was stable when stored at 4 degrees C. << Less
Arch. Biochem. Biophys. 322:183-188(1995) [PubMed] [EuropePMC]
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A novel methyl transferase induced by osmotic stress in the facultative halophyte Mesembryanthemum crystallinum.
Vernon D.M., Bohnert H.J.
Molecular mechanisms of osmotic stress tolerance were studied in Mesembryanthemum crystallinum (ice plant), a facultative halophyte capable of adjusting to and surviving in highly saline conditions. We screened a subtracted cDNA library enriched for salt stress-induced mRNAs to identify transcript ... >> More
Molecular mechanisms of osmotic stress tolerance were studied in Mesembryanthemum crystallinum (ice plant), a facultative halophyte capable of adjusting to and surviving in highly saline conditions. We screened a subtracted cDNA library enriched for salt stress-induced mRNAs to identify transcripts involved in this plant's adaptation to salinity. One mRNA, Imt1, was found to be up-regulated in leaves and, transiently, in roots. Nuclear run-on assays indicated that this mRNA is transcriptionally regulated. Imt1 encoded a predicted polypeptide of M(r) 40,250 which exhibited sequence similarity to several hydroxymethyl transferases. Expression of the protein in Escherichia coli and subsequent activity assays identified the protein as a novel myoinositol O-methyl transferase which catalyzes the first step in the biosynthesis of the cyclic sugar alcohol pinitol. Pinitol accumulates in salt-stressed M.crystallinum and is abundant in a number of salt- and drought-tolerant plants. The presence of high levels of sugar alcohols correlates with osmotolerance in a diverse range of organisms, including bacteria, fungi and algae, as well as higher plants. The stress-initiated transcriptional induction of IMT1 expression in a facultative halophyte provides strong support for the importance of sugar alcohols in establishing tolerance to osmotic stress in higher plants. << Less