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Methylmethionine sulfonium

CH3CI 74-87-3) see Atropine methonitrate Clobazam Dimethyltubocurarinium chloride Methylmethionine sulfonium chloride Naproxen Suxamethonium chloride methyl chloroacetate... [Pg.2413]

This enzyme [EC 3.3.1.2], also referred to as -adenosyl-methionine cleaving enzyme and methylmethionine-sulfonium-salt hydrolase, catalyzes the hydrolysis of -adenosylmethionine to produce methylthioadenosine and homoserine. The enzyme will also convert methyl-methionine sulfonium salt to dimethyl sulfide and homoserine. [Pg.34]

The reaction mixture (final volume 0.34 ml) contained (in /umol and including compounds added with the enzyme) potassium phosphate, pH 6.3, 102 Tris, pH 7.6, 5 sucrose, 13 GSH, 16 2-mercaptoethanol, 0.7 Na EDTA, 0.5. Methyl donors were added at the specified final concentrations. The various stereoisomeric forms of S-adenosylmethionine were prepared as described by de la Haba el al. (1959) using adenosylmethionine cyclotransferase (E.C. 2.5.1.4) to resolve (/(S)-S-adenosyl-L-methionine to (f )-5-adenosyl-L-methionine. The reaction was started by addition of enzyme dissolved in Tris buffer, pH 7.6, 25 mM, containing Na EDTA, 1 mM and 2-mercaptoethanol, 7 mM, and partially purified from an extract of cabbage leaves by successive ammonium sulfate precipitation (45-60% saturation), gel filtration (Sephadex G-25) and DEAE-cellulose column chromatography. After incubation at 26°C for 1 h, each reaction mixture was diluted with 0.76 ml cold water, and a 1.0 ml aliquot was immediately added to a column of Dowex-50(NHJ) 1 x 3 cm. Unreacted [ C]methionine was removed by washing the column with 25 ml water. The 5-[" C]methylmethionine sulfonium salt was then eluted with 8 ml 0.6 N NH OH. Radioactivity was determined by scintillation spectrophotometry (Mudd et al., 1965). A blank of 540 cpm has been subtracted from each value. The low activity with (R)-5-adenosyl-L-methionine may have been due to the presence of a small residual amount of (5)-5-adenosyl-L-methionine (de la Haba eta/., 1959). [Pg.494]

Rouillon, A., Surdin-Keijan, Y., Thomas, D. (1999). Transport of sulfonium compounds. Characterization of the S adenosylmethionine and S-methylmethionine permeases from the yeast Saccharomyces cerevisiae. J. Biol Chem., 274, 28096-28105. [Pg.271]

Methionine in plants can be converted to the sulfonium compound S-methyl-L-methionine, also called vitamin U. It has strong osmoprotectant activity and accumulates in many marine algae and some flowering plants.Other organisms, including mammals, can use S-methylmethionine to methylate homocysteine, converting both reactants back to methionine enabling animals to meet some of their methionine need from this source. [Pg.476]

Jencks (1969) has pointed out that the role of the enzyme itself is particularly difficult to understand in bimolecular displacement reactions in which general acid-base catalysis would give little advantage, or is not possible. As examples of such reactions Jencks included methyl transfer from S-adenosylmethionine to nicotinic acid to form the N-meth-yl pyridinium, trigonelline (Joshi and Handler, 1960), or to methionine to form the new sulfonium, S-methylmethionine (Greene and Davis,... [Pg.312]


See other pages where Methylmethionine sulfonium is mentioned: [Pg.1297]    [Pg.1297]    [Pg.2406]    [Pg.1297]    [Pg.454]    [Pg.1297]    [Pg.1297]    [Pg.2406]    [Pg.1297]    [Pg.454]    [Pg.1389]    [Pg.206]    [Pg.207]    [Pg.208]    [Pg.92]    [Pg.259]    [Pg.492]    [Pg.496]    [Pg.500]    [Pg.312]    [Pg.328]    [Pg.336]    [Pg.337]    [Pg.411]   


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2- Methylmethionine

Methylmethionine sulfonium chloride

Sulfonium

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