21681-94-7Relevant academic research and scientific papers
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.
Methyltransferase-directed derivatization of 5-hydroxymethylcytosine in DNA
Liutkeviaciute, Zita,Kriukiene, Edita,Grigaityte, Indre,Masevieius, Viktoras,Klimasauskas, Saulius
supporting information; experimental part, p. 2090 - 2093 (2011/04/23)
Sequence-specific derivatization: Enzymatic methylation of cytosine in DNA is part of an epigenetic regulatory network in vertebrates. In the absence of the methylation cofactor S-adenosyl-L-methionine, bacterial cytosine-5 methyltransferases can catalyze the condensation of aliphatic thiols and selenols with 5-hydroxymethylcytosine, a recently discovered nucleobase in mammalian DNA, to yield 5-chalcogenomethyl derivatives (see scheme).
