Emulating Antioxidative Functions of Glutathione Peroxidase Using Selenopeptides. In: Bayse CA, Brumaghim JL, editors. Biochalcogen Chemistry: The Biological Chemistry of Sulfur, Selenium, and Tellurium. Washington: American Chemical Society; 2013. pp. 163-77. [DOI: 10.1021/bk-2013-1152.ch008]

One-pot organocatalytic/multicomponent approach for the preparation of novel enantioenriched non-natural selenium-based peptoids and peptide-peptoid conjugates

A combined organocatalytic and multicomponent synthetic approach was designed for the preparation of selenium-based peptoids and peptide-peptoid conjugates. This single-step synthetic protocol comprises the organocatalytic asymmetric insertion of phenylselenium in the aldehyde moiety followed by the Ugi four-component reaction which results in obtaining the desired compounds in good-to-moderate yields and with good-to-excellent levels of stereoselectivity.

Selenoglutathione Diselenide: Unique Redox Reactions in the GPx-Like Catalytic Cycle and Repairing of Disulfide Bonds in Scrambled Protein

Selenoglutathione (GSeH) is a selenium analogue of naturally abundant glutathione (GSH). In this study, this water-soluble small tripeptide was synthesized in a high yield (up to 98%) as an oxidized diselenide form, i.e., GSeSeG (1), by liquid-phase peptide synthesis (LPPS). Obtained 1 was applied to the investigation of the glutathione peroxidase (GPx)-like catalytic cycle. The important intermediates, i.e., GSe^- and GSeSG, besides GSeO₂H were characterized by ⁷⁷Se NMR spectroscopy. Thiol exchange of GSeSG with various thiols, such as cysteine and dithiothreitol, was found to promote the conversion to GSe^- significantly. In addition, disproportionation of GSeSR to 1 and RSSR, which would be initiated by heterolytic cleavage of the Se-S bond and catalyzed by the generated selenolate, was observed. On the basis of these redox behaviors, it was proposed that the heterolytic cleavage of the Se-S bond can be facilitated by the interaction between the Se atom and an amino or aromatic group, which is present at the GPx active site. On the other hand, when a catalytic amount of 1 was reacted with scrambled 4S species of RNase A in the presence of NADPH and glutathione reductase, native protein was efficiently regenerated, suggesting a potential use of 1 to repair misfolded proteins through reduction of the non-native SS bonds.