21681-94-7Relevant articles and documents
A Comparative Study of the Kinetics of Selenol/Diselenide and Thiol/Disulfide Exchange Reactions
Pleasants, Joan C.,Guo, Wei,Rabenstein, Dallas L.
, p. 6553 - 6558 (1989)
The kinetics of symmetrical selenol/diselenide and thiol/disulfide exchange reactions involving selenocysteamine/selenocystamine and cysteamine/cystamine have been studied in D2O solution by NMR spectroscopy.The rate of selenol/diselenide exchange is so fast that resonances for the selenol and diselenide forms are coalesced in (1)H NMR spectra of millimolar selenocysteamine/selenocystamine mixtures at pD > 2-3.In contrast, the rate of thiol/disulfide exchange is so slow that separate, sharp resonances are observed for both cysteamine and cystamine in mixtures atconcentrations up to at least 0.2 M from pD 13.Rate constants for the selenol/diselenide exchange reaction were determined by line shape analysis of exchange-broadened resonances, while those for thiol/disulfide exchange were determined by an inversion-transfer method.The rate constants at 25 deg C for exchange by reaction of D3N(1+)CH2CH2X(1-) with D3N(1+)CH2CH2XXCH2CH2ND3(1+) are as follows: X = Se, k = 1.65 * 1E7 L/mol*s; X = S, k = 68.0 L/mol*s.When the differences in the acidities of the selenol and thiol groups are accounted for, selenocysteamine/selenocystamine exchange is 1.2 * 1E7 times faster than cysteamine/cystamine exchange at physiological pH.
Kinetics of reaction of peroxynitrite with selenium- and sulfur-containing compounds: Absolute rate constants and assessment of biological significance
Storkey, Corin,Pattison, David I.,Ignasiak, Marta T.,Schiesser, Carl H.,Davies, Michael J.
, p. 1049 - 1056 (2015/11/17)
Peroxynitrite (the physiological mixture of ONOOH and its anion, ONOO-) is a powerful biologically-relevant oxidant capable of oxidizing and damaging a range of important targets including sulfides, thiols, lipids, proteins, carbohydrates and nucleic acids. Excessive production of peroxynitrite is associated with several human pathologies including cardiovascular disease, ischemic-reperfusion injury, circulatory shock, inflammation and neurodegeneration. This study demonstrates that low-molecular-mass selenols (RSeH), selenides (RSeR') and to a lesser extent diselenides (RSeSeR') react with peroxynitrite with high rate constants. Low molecular mass selenols react particularly rapidly with peroxynitrite, with second order rate constants k2 in the range 5.1×105-1.9×106 M-1 s-1, and 250-830 fold faster than the corresponding thiols (RSH) and many other endogenous biological targets. Reactions of peroxynitrite with selenides, including selenosugars are approximately 15-fold faster than their sulfur homologs with k2 approximately 2.5×103 M-1 s-1. The rate constants for diselenides and sulfides were slower with k2 0.72-1.3×103 M-1 s-1 and approximately 2.1×102 M-1 s-1 respectively. These studies demonstrate that both endogenous and exogenous selenium-containing compounds may modulate peroxynitrite-mediated damage at sites of acute and chronic inflammation, with this being of particular relevance at extracellular sites where the thiol pool is limited.
Selenols Catalyze the Interchange Reactions of Dithiols and Disulfides in Water
Singh, Rajeeva,Whitesides, George M.
, p. 6931 - 6933 (2007/10/02)
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