- Glutathione-complexed iron-sulfur clusters. Reaction intermediates and evidence for a template effect promoting assembly and stability
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Assembly and stabilization of a glutathione-complexed [2Fe-2S] cluster is promoted by aggregation of glutathione. The cluster core selects the tetramer species from a collection of equilibrating solution aggregate species, and in turn the core is stabilized toward hydrolytic degradation. Studies of glutathione derivatives, in combination with mass spectrometric and Moessbauer investigations provide insight on reaction intermediates during formation of [2Fe-2S](GS)42-.
- Qi, Wenbin,Li, Jingwei,Chain,Pasquevich,Pasquevich,Cowan
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- METHOD FOR THE SYNTHESIS OF GLUTATHIONE DERIVATIVES
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A synthesis method for the production of N-acyl glutathione, comprising an acylation step, during which, in a water solution with a pH ranging from 8 to 10, glutathione is caused to react with an anhydride with formula (RCO)2O with a formation of S,N-diacyl glutathione, and a subsequent S-acyl group selective alcoholysis step, during which the S,N-diacyl glutathione produced in the previous step is dissolved in an alkoxide/alcohol solution (R'O-/R'OH) and, subsequently, the obtained product is treated with a cation-exchange resin. R is H or a straight or branched hydrocarbon group with a number of carbon atoms ranging from C1 to C24 while R' is a straight or branched radical hydrocarbon group with a number of carbon atoms ranging from C1 to C4.
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Page/Page column 6; 7
(2019/06/11)
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- Glutathione-complexed iron-sulfur clusters. Reaction intermediates and evidence for a template effect promoting assembly and stability
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Assembly and stabilization of a glutathione-complexed [2Fe-2S] cluster is promoted by aggregation of glutathione. The cluster core selects the tetramer species from a collection of equilibrating solution aggregate species, and in turn the core is stabilized toward hydrolytic degradation. Studies of glutathione derivatives, in combination with mass spectrometric and Moessbauer investigations provide insight on reaction intermediates during formation of [2Fe-2S](GS)42-.
- Qi, Wenbin,Li, Jingwei,Chain,Pasquevich,Pasquevich,Cowan
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supporting information
p. 6313 - 6315
(2013/08/23)
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- Rapid high-yield N-acylation of aminothiols: N-acetylglutathione and N-acetylhomocysteine and their thiol pKa values
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Methodology for the rapid N-acylation of aminothiols in aqueous solution using procedures commonly employed in biochemical studies is described here. Glutathione disulfide (GSSG) and homocystine were diN-acetylated in ~100% yield in 0.1M aqueous NaHCO3 (pH 8.5) at room temperature by 2.5equiv of the activated ester, N-hydroxysulfosuccinimidyl acetate, an efficient water-soluble acetylating reagent. Following acetone precipitation, diN-acetylGSSG was further purified and desalted on a strong anion-exchange (SAX) cartridge. DiN-acetylhomocystine was simultaneously purified and desalted on a C18 cartridge. The N-acetylated aminothiols were generated using gel-immobilized tris(2-carboxyethyl)phosphine as a reductant, which obviated the need for further purification. Alternatively, disulfide exchange with dissolved dithiothreitol yielded N-acetylglutathione, which was purified on the SAX cartridge. pH titrations of N-acetylglutathione (8.99) and N-acetylhomocysteine (9.66) as well as those of commercially available N-acetylcysteine (9.53) and N-acetylpenicillamine (10.21) yielded pKa(SH) values of importance for biological studies.
- Shen, Biao,Bazin, Cynthia,English, Ann M.
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p. 263 - 267
(2013/07/05)
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- Ring addition of the α-amino group of glutathione increases the reactivity of benzoquinone thioethers
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2-(Glutathion-S-yl)-1,4-benzoquinone was found to be remarkably unstable in phosphate butter (pH 7.4) even in the absence of oxygen. Intramolecular addition of the α-amino group of the glutamate residue to the quinone ring yielded ultimately 2,3-(glutathion-N,S-yl)-1,4-benzoquinone and 2,6- (glutathion-N,S-yl)-1,4-benzoquinone in a 3:1 ratio along with 2-(glutathion- S-yl)-1,4-hydroquinone. Kinetic studies indicated that the cyclization reactions proceeded at a rate k1 of 0.093 min-1, while intermolecular reactions followed a second-order kinetics with a k2 of 94 M-1 min-1 (pH 7.4, 37 °C), resulting in multiple polymerization products. Both intramolecular amino adducts of 2-(glutathion-S-yl)-1;4-benzoquinone are prone to hydrolysis, leading to the insertion of an additional OH group in the ring. These S-substituted trihydroxybenzene derivatives are particularly susceptible to autoxidation. The model compound 6-(N-acetylcystein-S-yl)-2- hydroxy-1,4-hydroquinone was shown to form readily two atropoisomeric biphenyls upon autoxidation: 2,4'-bis(N-acetylcystein-S-yl)-2',3,3',4,6,6'- hexahydroxybiphenyl, indicating C-C coupling, presumably via semiquinone radical intermediates. Thus, the sequence of glutathione S-addition, followed by oxidation, N-addition, oxidation, an 1 hydrolysis, constitutes a novel and very effective activation pathway of quinones for eliciting oxidative stress. These data underline the fact that glutathione conjugates of autoxidizable aromatics are no obligatory stable end products of a detoxication reaction. The possible toxicological impacts of intra- and intermolecular addition reactions of quinoid thiol conjugates are discussed.
- Alt, Carmen,Eyer, Peter
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p. 1223 - 1233
(2007/10/03)
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