S-Methyl cysteine

In aqueous solutions at pH 7, there is little evidence of complex formation between [MesSnflV)] and Gly. Potentiometric determination of the formation constants for L-Cys, DL-Ala, and L-His with the same cation indicates that L-Cys binds more strongly than other two amino acids (pKi ca. 10,6, or 5, respectively). Equilibrium and spectroscopic studies on L-Cys and its derivatives (S-methyl-cystein (S-Me-Cys), N-Ac-Cys) and the [Et2Sn(IV)] system showed that these ligands coordinate the metal ion via carboxylic O and the thiolic 5 donor atoms in acidic media. In the case of S-Me-Cys, the formation of a protonated complex MLH was also detected, due to the stabilizing effect of additional thioether coordination. ... 

The acid-catalysed oxidation of a protected S-methyl cysteine, which gives poor diastereoselectivity when oxidized in conventional solvents, shows density-dependent diastereoselectivity as shown in scheme 6.1 [8], Here, tert-butyl hydrogen peroxide (TBHP) is used as the oxidant and the reaction is catalysed by an Amberlyst resin (a solid acid). By tuning the pressure at which this reaction was carried out, almost 100% selectivity to one diastereomer could be achieved (Figure 6.4). 

In all of the above reactions, a chiral center of the alkene was located in the allylic position. However, as shall be demonstrated next, more distant chiral centers may also lead to highly selective cycloadditions with 1,3-dipoles. In two recent papers, the use of exocyclic alkenes has been applied in reactions with C,N-diphenylnitrone (165,166). The optically active alkenes 109 obtained from (S)-methyl cysteine have been applied in reactions with nitrones, nitrile oxides, and azomethine ylides. The 1,3-dipolar cycloaddition of 109 (R=Ph) with C,N-diphenyl nitrone proceeded to give endOa-1 Q and exOa-110 in a ratio of 70 30 (Scheme 12.36). Both product isomers arose from attack of the nitrone 68 at the... 

O -KG = a-ketoglntarate ACmC = 5-(L-a -aminoadipoyl)-L-cysteinyl-L-S-methyl-cysteine ACOY = S-(L-a-... 

CH3SH Methionine, methionine sulfoxide, methionine sulfone, S-methyl cysteine... 

S-methylglutathione, S-methyl cysteine, and other sulfur-containing compounds. 

E Bailey, PB Farmer, JH Lamb. The enantiomer as internal standard for the quantitation of the alkylated amino acid S-methyl-cysteine in haemoglobin by GC-CI-MS with single ion detection. J Chromatogr 200 145—152, 1980. 

Organosulphur compounds, e.g., S-methyl cysteine sulphoxide (SMCSO) and its metabolite methyl methane thiosulphinate, both naturally occurring compounds present in Brassica vegetables (broccoli, cabbage) were found to inhibit benzo[a]pyrene-induced micronucleus formation in mouse bone marrow by 31 and 33%, respectively, after oral administration (Marks et al. 1993). 

Marks HS, Anderson JA, Stoewsand GS. 1993. Effect of S-methyl cysteine sulphoxide and its metabolite methyl methane thiosulphinate, both occuring naturally in brassica vegetables, on mouse genotoxicity. Food Chem Toxic 31 (7) 491-495. 

Proteins, polypeptides, cystine, cysteine, gluthathione Methionine, methionine sulfoxide, methionine sulfone, S-methyl cysteine Methionine, methionine sulfoxide, methionine sulfone, S-methyl cysteine, homocysteine... 

S-alkyl cysteines, such as S-allyl cysteine (SAC), S-methyl cysteine (SMC), and S-propyl cysteines are slowly formed during sprouting from the action of y-glutamyl transpeptidase on y-glutamyl cysteines. S-allyl cysteine is also rapidly formed in the body by hydrolysis of y-glutamyl cysteine particularly in the kidney which contains an abundant amount of Y-glutamyl transpeptidase activity [2]. 

S-Methyl cysteine (SMC) and cysteine exerted significant inhibitory effects to decrease the number of glutathione S-transferase placental form (GST-P)-positive foci when given in the promotion stage of the Ito test. 

L-2-Amino-3-(methylthio)- HL/H.L propanoic acid (S-methyl-cysteine) (C H O NS), HL... 

Rinderknecht, H., D. Thomas und S. Aslin y-Glutamyl-S-methyl-cystein und andere Peptide in der Mondbohne (Phaseolus lunatus L.). Helv. Chim. Acta 41, 1 (1958). 

For the biosynthesis of iS-methyl cysteine sulfoxide, methyl donor can be methionine because the radioactively labeled methionine could be incorporated into the S-methyl cysteine and iS-methyl cysteine sulfoxide (Sugii et al. 1963 Granroth 1970) (Figure 18.3). Regarding the S-methyl glutathione was detected in garlic (Lancaster and Shaw 1989 ... 

FIGURE 18.5. Formation of flavor compounds from S-allyl cysteine sulfoxide and S-methyl cysteine sulfoxide. 

Kale contains an imbalance of trace elements such as iodine and manganese and a chemical called S-methyl cysteine sulphoxide (SMCO) very high intakes should be avoided as they can lead to haemolytic anaemia and fertility problems. 

As the four microscopic constants cannot be determined by a titration curve, spectrophotometric analysis (UV absorption of R-S ) was necessary. The pX (8.65) of cysteine betaine (ionization of a thiol in the presence of a positive nitrogen) and the pK (8.75) of S-methyl cysteine (ionization of an amino group in the presence of neutral sulfur) closely mimic the and /c2 dissociation pathways and suggest that these values should be close to each other... 

In both, the cadmium(II) S-methyl-cysteine and methionine systems, mono-, bis-, and tris(ligand) complexes are formed corresponding to the six-coordinated octahedral geometry of cadmium(II). Although the corresponding zinc(ll) complexes... 

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