5- Methylmethionine

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

Another source (Equation 9) is lyase action on 5-methylmethionine ... 

Fig. 2.4 The S-methylmethionine cycle and its interaction with the activated methyl cycle. The SMM cycle operates within the activated methyl cycle, and in effect short-circuits it. The reactions mediated by MMT and HMT are shown in bold. THF, tetrahydrofolate CH2-THF, 5,10-methylenetetrahydrofolate,...

Fig. 8.1 Proposed synthetic pathways for dimethylsulfoniopropionate from methionine for three algal and plant species. DMSHB 4-dimethylsulfio-2-hydroxy-butyrate, MTHB 4-methylthio-2-hydroxybutyrate, MTOB 4-methylthio-2-oxobutyrate, SMM S-methylmethionine...

Hanks R (1966) Observations on milky water in Chesapeake Bay. Chesapeake Sci 7 175-176 Hanson A, Rivoal J, Paquet L, Gage D (1994) Biosynthesis of 3-dimethylsulfoniopropionate in Wollastonia biflora (L.) DC evidence that S-methylmethionine is an intermediate. Plant Physiol 105 103-110... 

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. 

GS158 Ohtsuki, K., M. Kawabata, K. Taguchi, H. Kokura and S. Kawamura. Determination of S-methylmethionine, vitamin U, in various teas. Agr Biol Chem 1984 48(10) 2471-2475. 

Although the most generally useful heterocycles for the alkylation of simple amino acids by this method are the imidazolidinones84, oxazolidinones have the advantage of being much more readily hydrolyzed. (S)-a-Methylmethionine was prepared by this latter method from the parent amino acid 85,86. The oxazolidinone 1885 [mp 126.4-127.2 °C [a]D +61.8 (e = 1, CHC13)] prepared in 24-30% yield from (S)-methionine, was methylated using LDA and iodomethane in satisfactory yield. 

Few accounts of the reactions of coordinated ligands have been published. One recent report indicates that the copper complex of S-methylmethionine yields the copper complex of a-amino-y-butyrolactone and dimethyl sulfide upon heating.8 ... 

Kovatcheva [12] has described a method using an automated amino acid analyser for the determination of S-methylmethionine in cabbage, kohlrabi, celery and sweetcorn. The plant sample is first homogenised with 0.1N hy-... 

Figure 8.1. Chromatograms produced on a 100 mm column of an amino acid analyser with 0.3 N sodium citrate solution (pH 7.00) as eluting agent (a) standard solution containing 1 unol/ml of each amino acid (b) 30 g of cabbage extract purified with Dowex 50-X8 in the ammonium form (0.97 mg of S-methylmethionine) and (c) the same sample as for (b) but after treatment at pH 10.0 for 30 minutes at 120 C. MMS S-methylmethionine, fils histidine, lys lysine, orn ornithine, arg arginine. From [12]...

Following adjustment to pH 6.0, the solution is applied to a SP-Sephadex C-25 column in the sodium form. Amino acids are then eluted with 0.2 M citrate phosphate buffer, pH 8.0, and the effluent evaporated to dryness at 50 °C. The residue is dissolved in 0.1 N hydrochloric acid and applied to the amino acid analyser. Amino acids are separated by passing 0.2 M, pH 8 sodium citrate solution down the column. The S-methylmethionine content can then be obtained from the chromatogram, as illustrated in Fig. 8.1. The results obtained agree reasonably well with those obtained by thin-layer chromatography [13]. 

White (22) has shown that DMS is found in numerous marine macroalgae after alkaline treatment (Table II). He also presented data that indicated two pools of DMS precursors in marine algae. He demonstrated that a relatively stable compound released DMS only after alkaline hydrolysis at 100°C for 2 hours, and speculated that this compound may be S-methylmethionine. 

DMS is formed during the biodegradation of organic sulfur compounds and by the biological methylation of sulfide and methanethiol. Precursors of DMS are methionine, S-methylmethionine, dimethylsulfoniopropionate (DMSP), dimethylsulfonioacetate (DMSA), dimethyl sulfoxide (DMSO), methionine sulfoxide and sulfone, trimethylsulfonium salts, S-methylcysteine, homocysteine, dimethyl disulfide (DMDS), 2-keto-4-methiolbutyrate, and 2-mercaptoacetate (thioglycollate). 

Methionine and its S-methyl derivative, S-methylmethionine, are probably important precursors of DMS in terrestrial regions. However, plants also produce a variety of nonprotein sulfur amino adds such as S-methylcysteine, its 7-glutamyl and sulfoxide derivatives, and djenkolic add (44). The biosyntheses and functions of these compounds are poorly understood, and mechanisms for their biodegradation may be of more than academic interest, particularly with respect to the generation of volatile sulfur compounds. 

Methionine 7 -lyase Methionine Homocysteine S-methylcysteine Methionine sulfoxide Methionine sulfone S-methylmethionine (weak) Methanethiol HtS Methanethiol DMS... 

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