Aryl Thiol Substrate 3-Carboxy-4-Nitrobenzenethiol Strongly Stimulating Thiol Peroxidase Activity of Glutathione Peroxidase Mimic 2, 2'-Ditellurobis(2-Deoxy- 详细信息    查看全文

• 作者：Zeyuan Dong ; Junqiu Liu ; Shizhong Mao ; Xin Huang ; Bing Yang ; Xiaojun Ren ; Guimin Luo ; and Jiacong Shen
• 刊名：Journal of the American Chemical Society
• 出版年：2004
• 出版时间：December 22, 2004
• 年：2004
• 卷：126
• 期：50
• 页码：16395 - 16404
• 全文大小：240K
• 年卷期：v.126,no.50(December 22, 2004)
• ISSN：1520-5126

文摘

Artificial glutathione peroxidase (GPx) model 2, 2'-ditellurobis(2-deoxy--cyclodextrin) (2-TeCD)which has the desirable properties exhibited high substrate specificity and remarkably catalytic efficiencywhen 3-carboxy-4-nitrobenzenethiol (ArSH) was used as a preferential thiol substrate. The complexationof ArSH with -cyclodextrin was investigated through UV spectral titrations, fluorescence spectroscopy, ¹HNMR and molecular simulation, and these results indicated that ArSH fits well to the size of the cavity of-cyclodextrin. Furthermore, 2-TeCD was found to catalyze the reduction of cumene peroxide (CuOOH)by ArSH 200 000-fold more efficiently than diphenyl diselenide (PhSeSePh). Its steady-state kinetics wasstudied and the second rate constant k_max/K_ArSH was found to be 1.05 × 10⁷ M^-1 min^-1 and similar to thatof natural GPx. Moreover, the kinetic data revealed that the catalytic efficiency of 2-TeCD depended stronglyupon the competitive recognition of both substrates for 2-TeCD. The catalytic mechanism of 2-TeCD catalysisagreed well with a ping-pong mechanism, in analogy with natural GPx, and might exert its thiol peroxidaseactivity via tellurol, tellurenic acid, and tellurosulfide.