The Reaction Mechanism Of Glutathione And Selenium

Selenite has been found to be an active catalyst for the oxidation of sulfhydryl compound, such as GSH. Considering the biological importance of GSH oxidation and the implication of sulfhydryl compounds in selenium poisoning and other biological activities, more information on selenite oxidation of GSH in enzyme-free conditions is desirable. Herein, we describes glutathione and sodium selenite simply mixed in aqueous solutions, the interaction products and transient intermediate were identified and characterized by using dynamic ESI tandem mass spectrometry. The mixture solutions were also characterized by using dynamic UV-vis spectrometry and ~1H-NMR spectrometry. The experiment results indicated that dynamic redox reactions take place between GSH and selenite. In the first step, GSH is directly oxidated to form diglutathione and unstable selenodiglutathone(GS-Se-SG) intermediate. Then the unstable selenodiglutathione intermediate further reacted with lelt GSH to form diglutathione and elemental selenium Se~0. As the amount of GSSG significantly increased or acidity of the solution increased , the redox potential of GSH(E~0'(GSSG/2GSH) = -250mV(NHE)) significantly shifted to the positive direction, which makes the GSSG have more oxidant properties and leads to the redox reactions between GSSG and Se, which can be demonstrated by another unstable intermediate anions(m/z 418 [GSS-Se]~-). The reaction mechanism between GSH and sodium selenite is proposed through the dynamic ESI-MS, 1H-NMR and UV-vis spectrometric measurements.Furthermore, we also synthesize Selenium nanoparticles in aqueous solution by using chitosan (CTS) as a soft template. In this part experiment, we study many factors which can affect the size and form of the product. The factors include reaction time, concentration of reactants and ultrasonic irradiation. After 3h reaction of the mixture...