Applications of Water-Soluble Selenides and Selenoxides to Protein Chemistry

A Water‐Soluble Cyclic Selenide with Enhanced Glutathione Peroxidase‐Like Catalytic Activities

“…Methanol (CD 3 OD) was selected as a solvent in this assay because the reaction proceeded too fast in water to be monitored by 1 H NMR spectroscopy. [12] In the series of the 1 H NMR spectra (Figure 2), the absorptions at δ = 2.63, 3.67 ppm due to DTT red decreased with increasing reaction time, whereas those at δ = 2.87, 3.03, 3.49 ppm due to DTT ox increased. In the absence of a catalyst, 86 % of DTT red remained unreacted after 300 min ( Figure 3).…”

“…In methanol, however, selenoxide 7 gradually decomposed into unknown compounds: such degradation products were previously observed in the 1 H NMR spectra. [12] The degradation would be responsible for the low catalytic activity of 4 in methanol (see Figure 3) despite the largest reduction ability among the selenides. It is of particular interest that cyclic selenide 1 can be oxidized more easily than linear selenide 3 and resulting cyclic selenoxide 2 can be reduced more easily than linear selenoxide 6.…”

“…In the NMR assay, [12] DTT red (0.15 mmol) and selenide (0.015 mmol) were dissolved in CD 3 OD (1.1 mL), and the solution was added to 30 % H 2 O 2 (17 µL, 0.15 mmol) to start the reaction. 1 H NMR spectra were measured at a variable reaction time at 25°C.…”

“…Selenoxide 7 was stable only in solution and could not be isolated. [12] Other chemicals and enzymes were purchased from chemical companies and used without purification. 1 H, 13 C, and 77 Se NMR spectra were recorded at 500, 125.77, and 95.43 MHz, respectively, at 25°C by using CHCl 3 , CDCl 3 , and (PhSe) 2 as the external standards for 1 H, 13 Activity Measurements: Catalytic activities of the selenides were measured as follows by using GSH, DTT red , and reduced RNase A (R) as a thiol substrate according to the literature methods.…”

Synthesis, characterization, structures and antioxidant activity of nicotinoyl based organoselenium compounds

“…The catalytic activity of organoselenium compounds as GPx mimics was also evaluated by NMR route employing the method reported by Iwaoka et al [21,31]. In this method reduction of hydrogen peroxide, using DTT red (reduced dithiothreitol) as thiol cofactor was monitored by 1 H NMR spectroscopy.…”