- Selenols are resistant to irreversible modification by HNO
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The discovery of nitric oxide (NO) as an endogenously generated signaling species in mammalian cells has spawned a vast interest in the study of the chemical biology of nitrogen oxides. Of these, nitroxyl (azanone, HNO) has gained much attention for its potential role as a therapeutic for cardiovascular disease. Known targets of HNO include hemes/heme proteins and thiols/thiol-containing proteins. Recently, due to their roles in redox signaling and cellular defense, selenols and selenoproteins have also been speculated to be additional potential targets of HNO. Indeed, as determined in the current work, selenols are targeted by HNO. Such reactions appear to result only in formation of diselenide products, which can be easily reverted back to the free selenol. This characteristic is distinct from the reaction of HNO with thiols/thiolproteins. These findings suggest that, unlike thiolproteins, selenoproteins are resistant to irreversible oxidative modification, support that Nature may have chosen to use selenium instead of sulfur in certain biological systems for its enhanced resistance to electrophilic and oxidative modification.
- Bianco, Christopher L.,Moore, Cathy D.,Fukuto, Jon M.,Toscano, John P.
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- Design and synthesis of new 2-aryl-4,5-dihydro-thiazole analogues: In vitro antibacterial activities and preliminary mechanism of action
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Sixty 2-aryl-4,5-dihydrothiazoles were designed and synthesized in yields ranging from 64% to 89% from cysteine and substituted-benzonitriles via a novel metal- and catalyst-free method. The structures of the title compounds were confirmed mainly by NMR spectral data analysis. Antibacterial activity assays showed that the compounds (S)-2-(2′-hydroxyphenyl)-4-hydroxy-methyl-4,5-dihydrothiazole (7h) and (R)-2-(2′-hydroxyphenyl)-4-hydroxymethyl-4,5-dihydro-thiazole (7h′) exhibited significant inhibition against Ralstonia solanacearum, Pseudomonas syringae pv. actinidiae, Bacillus subtilis and Bacillus cereus, with minimum inhibitory concentrations (MICs) ranging from 3.91 to 31.24 μg·mL-1. The effect of substituents showed that not only electron-withdrawing groups, but also electron-donating groups could abolish the antibacterial activities unless a 2′-hydroxy group was introduced on the 2-aryl substituent of the 4,5-dihydrothiazole analogues. The results of scanning electron microscope (SEM) and fatty acid exposure experiments indicated that these antibacterial compounds influence fatty acid synthesis in the tested bacteria.
- Tan, Fangfang,Shi, Baojun,Li, Jian,Wu, Wenjun,Zhang, Jiwen
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p. 20118 - 20130
(2015/12/23)
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- The prop-2-ynyloxy carbonyl function (POC): A new amino-protecting group removable from sulfur-containing peptides by ultrasonic irradiation with tetrathiomolybdate under mild and neutral conditions
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The prop-2-ynyloxy carbonyl function (POC) which can be cleaved under mild and neutral conditions in the presence of benzyltriethylammonium tetrathiomolybdate has been developed as a new protecting group for amines.
- Sinha, Surajit,Ilankumaran, Palanichamy,Chandrasekaran, Srinivasan
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p. 771 - 774
(2007/10/03)
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- Fluorescent and Nonfluorescent Aryl Vinyl Sulfones - Reagents Suitable for Protection and Detection of Thiol Functions
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The rate of the addition of primary, secondary, and tertiary thiols to aryl/alkyl vinyl sulfones 1 and 4-7 is investigated by competing reactions and by kinetics.The obtained acid stable 2-(alkyl-/arylthio)ethyl sulfones are cleaved by bases to give the starting material by rates corresponding to the rates of addition.Therefore, selective introduction and selective elimination of different (arylsulfonyl)ethyl protective groups in the same molecule is possible by using different kinetic steering factors. - Application of the fluorescent vinyl sulfones 5, 10, and 11 opens new fields for analysis and synthesis.SH-selective vinyl sulfones and thiophosphinic acid cyanides are "orthogonal" protective groups.
- Horner, Leopold,Lindel, Hans
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