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writer：Dong, ZY; Liu, JQ; Mao, SZ; et al.
keywords：Glutathione peroxidase, Cyclodextrin, Enzyme models, Catalysis
source：期刊
Issue time：2006年
Glutathione peroxidase (GPx) is one of the most important antioxidative selenoenzymes in living organisms. The novel GPx mimic 6,6’-ditellurobis(6-deoxy-b-cyclodextrin) (6-TeCD) was prepared and evaluated for its capacity to catalyze the reduction of H₂O₂, tert-butyl hydroperoxide (t-BuOOH), and cumene hydroperoxide (CuOOH) by glutathione (GSH) or 3-carboxy-4-nitrobenzenethiol (ArSH). Compared the ArSH assay with the coupled reductase assay, 6-TeCD exhibited strong substrate specificity for aromatic thiol substrate. The specificity led to efficient peroxidase activity almost 100,000-fold than that for a well-known GPx mimic diphenyl diselenide (PhSeSePh). Furthermore, reduction of lipophilic CuOOH proceeded ca. 30 times faster than the more hydrophilic H₂O₂, which cannot bind into the hydrophobic cavity of b-cyclodextrin. Thus, it seems that catalytic activity of cyclodextrin-derived GPx models strongly depends on the structurally different both substrates hydroperoxides (ROOH) and thiols.