113869-17-3Relevant academic research and scientific papers
Modelling the Inhibition of Selenoproteins by Small Molecules Using Cysteine and Selenocysteine Derivatives
Reddy, Kishorkumar M.,Mugesh, Govindasamy
, p. 8875 - 8883 (2019/06/17)
Small molecule-based electrophilic compounds such as 1-chloro-2,4-dinitrobenzene (CDNB) and 1-chloro-4-nitrobenzene (CNB) are currently being used as inhibitors of cysteine- and selenocysteine-containing proteins. CDNB has been used extensively to determine the activity of glutathione S-transferase and to deplete glutathione (GSH) in mammalian cells. Also, CDNB has been shown to irreversibly inhibit thioredoxin reductase (TrxR), a selenoenzyme that catalyses the reduction of thioredoxin (Trx). Mammalian TrxR has a C-terminal active site motif, Gly-Cys-Sec-Gly, and both the cysteine and selenocysteine residues could be the targets of the electrophilic reagents. In this paper we report on the stability of a series of cysteine and selenocysteine derivatives that can be considered as models for the selenoenzyme–inhibitor complexes. We show that these derivatives react with H2O2 to generate the corresponding selenoxides, which undergo spontaneous elimination to produce dehydroalanine. In contrast, the cysteine derivatives are stable towards such elimination reactions. We also demonstrate, for the first time, that the arylselenium species eliminated from the selenocysteine derivatives exhibit significant redox activity by catalysing the reduction of H2O2 in the presence of GSH (GPx (glutathione peroxidase)-like activity), which suggests that such redox modulatory activity of selenium compounds may have a significant effect on the cellular redox state during the inhibition of selenoproteins.
Model Compounds for the Active Site Selenocysteine of Glutathione Peroxidase: a 77Se NMR Study
Dowd, Diane,Gettins, Peter
, p. 1 - 3 (2007/10/02)
To test the feasibility of using 77Se NMR to distinguish between different proposed mechanisms of action of the selenoenzyme glutathione peroxidase, model compounds containing the proposed selenium moieties have been synthesized and their 77Se NMR spectra recorded.It was found that the difference in chemical shift between the two proposed resting states, selenol or selenenic acid, is approximately 1300 ppm.For the next step, oxidation by hydrogen peroxide, a much smaller difference of about 100 ppm was found between selenenic and seleninic acid species.The products of the second reaction step, selenide sulfide vs selenoxide sulfide, differed in chemical shift by about 470 ppm.It was concluded that, for two of the three states of the enzyme, 77Se NMR could, in principle, be used unambiguously to distinguish between the two proposed mechanisms.KEY WORDS: 77Se NMR; glutathione peroxidase selenoenzyme; selenium model compounds.
