- S-Alk(en)ylmercaptocysteine: Chemical synthesis, biological activities, and redox-related mechanism
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S-Alk(en)ylmercaptocysteine (CySSR, R = methyl, ethyl, propyl, 1-propenyl, and allyl), which are the putative metabolites of Allium thiosulfinates, were chemically synthesized. CySSR, but not the corresponding monosulfide species S-alk(en)yl cysteine (CyS
- Zhang, Guodong,Parkin, Kirk L.
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- Cysteine and glutathione mixed-disulfide conjugates of thiosulfinates: Chemical synthesis and biological activities
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The chemical syntheses of cysteine (CYS) and glutathione (GSH) mixed -disulfide conjugates (CySSR, GSSR, respectively) of mercapto residues representing most of the R groups of thiosulfinates (R = methyl, ethyl, propyl, and allyl) are described. Gram-scale conjugates were prepared as >98% pure preparations, with 80% reaction yield for each of the two seminal synthesis steps, with structures confirmed by 1H NMR and high-resolution MS analyses. These conjugates are derivatives of thiosulfinates that may be evolved in processed foods, in the digestive tract, and through in vivo metabolism. The prepared conjugates were found to be able to induce quinone reductase (QR, a representative phase II enzyme) in murine hepatoma cells (Hepa 1c1c7) and to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated macrophage cells (RAW 264.7), indicating they have potential cancer preventive and anti-inflammatory activities. Among the prepared conjugates, the allyl conjugates of CYS and GSH, S-allylmercaptocysteine (CySSA) and S-allylmercaptoglutathione (GSSA), showed the most potent activity regarding QR induction and NO production inhibition. The conjugates with saturated R groups were also active and conferred biological activity as cystine and oxidized glutathione exhibited no effects in these cellular assays.
- Zhang, Guodong,Ll, Bln,Lee, Chen-Hsien,Parkin, Klrk L.
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- A tissue homogenate method to prepare gram-scale allium thiosulfinates and their disulfide conjugates with cysteine and glutathione
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The health benefits of Allium vegetables are widely attributed to the enzyme-derived organosulfur compounds called thiosulfinates (TS). However, the lack of a suitable method to prepare TS in good yields has hampered the evaluation of their biological activities. This paper describe a simple enzymatic method using Allium tissue homogenates as a reaction system to prepare gram-scale TS, including those enriched in 1-propenyl groups, which are particularly difficult to obtain. This method is simple, easy to scale up, and requires no column purification step, making it suitable for practical large-scale production of Allium TS. The prepared TS were further utilized to prepare the disulfide conjugates with cysteine and glutathione (CySSR and GSSR, R = methyl, ethyl, propyl, 1-propenyl, and allyl), which are the presumptive metabolites of TS. Among all of the Allium CySSR and GSSR conjugates, the newly prepared glutathione conjugate with 1-propenyl TS, GSSPe, showed the most potent effect to induce quinone reductase (QR, a representative phase II enzyme) in murine hepatoma cells (Hepa 1c1c7) and inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated macrophage cells (RAW 264.7).
- Zhang, Guodong,Parkin, Kirk L.
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p. 3030 - 3038
(2013/08/25)
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- A facile method for the preparation of S-(alkylsulfenyl)cysteines)
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A general method for the facile preparation of S-(alkylsulfenyl)cysteines is described. It employs S-(methoxycarbonylsulfenyl)cysteine hydrochloride [H-Cys(Scm)-OH.HCl] as an easily accessible parent thiol-activated cystein derivative.
- Rietman,Peters,Tesser
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p. 1323 - 1332
(2007/10/02)
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- Selectively S-Protected Cysteine Peptides. IV. Synthesis of Cysteine Peptides Using the S-Ethylthio Protecting Group. II
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Studying the problems of the selective sulphur protection in cysteine peptides, a model octapeptide from the sheep insulin A-chain was prepared by conventional synthesis using the S-ethylthio and the S-diphenylmethyl group.As consequence of the small acid
- Kunzek, Herbert,Rose, Karl-Berthold,Graetz, Solveyg,Nesener, Eckehard
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p. 186 - 198
(2007/10/02)
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