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聚苯胺尿酸酶电极性能的研究 总被引:4,自引:1,他引:4
依据pH对聚苯胺尿酸酶电极最大响应电流的影响, logim~pH图表明尿酸酶电极的催化活性只与其电离基团的碱性形式有关. 扫描电镜的结果表明, 聚苯胺尿酸酶电极的稳定性与其制备方法有关. 电化学法固定的尿酸酶电极具有高的稳定性. 相似文献
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Zhao Y Kan ZY Zeng ZX Hao YH Chen H Tan Z 《Journal of the American Chemical Society》2004,126(41):13255-13264
Nucleic acid molecules may fold into secondary structures, and the formation of such structures is involved in many biological processes and technical applications. The folding and unfolding rate constants define the kinetics of conformation interconversion and the stability of these structures and is important in realizing their functions. We developed a method to determine these kinetic parameters using an optical biosensor based on surface plasmon resonance. The folding and unfolding of a nucleic acid is coupled with a hybridization reaction by immobilization of the target nucleic acid on a sensor chip surface and injection of a complementary probe nucleic acid over the sensor chip surface. By monitoring the time course of duplex formation, both the folding and unfolding rate constants for the target nucleic acid and the association and dissociation rate constants for the target-probe duplex can all be derived from the same measurement. We applied this method to determine the folding and unfolding rate constants of the G-quadruplex of human telomere sequence (TTAGGG)(4) and its association and dissociation rate constants with the complementary strand (CCCTAA)(4). The results show that both the folding and unfolding occur on the time scale of minutes at physiological concentration of K(+). We speculate that this property might be important for telomere elongation. A complete set of the kinetic parameters for both of the structures allows us to study the competition between the formation of the quadruplex and the duplex. Calculations indicate that the formation of both the quadruplex and the duplex is strand concentration-dependent, and the quadruplex can be efficiently formed at low strand concentration. This property may provide the basis for the formation of the quadruplex in vivo in the presence of a complementary strand. 相似文献
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Shengdong Zang Jingru Guo Anzhi Cui Daming Li Daming Liu 《Journal of Radioanalytical and Nuclear Chemistry》1996,212(2):93-99
The half-life of126Sn has never been measured accurately. The value quoted in the literature is approximately 105y, which was measured in 1958. In the present work we measured accruately the half life of126Sn to be (2.5±0.2)×105y using a radiochemical method. 相似文献
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Jingqi Guan ShuBo Jing Shujie Wu Haiyan Xu Zhenlv Wang Qiubin Kan 《Reaction Kinetics and Catalysis Letters》2007,90(1):27-33
A series of MoV0.3Tex (x = 0−0.3) mixed oxides were prepared and investigated for the selective oxidation of isobutane. Among them, MoV0.3Te0.23 showed the best methacrolein and methacrylic acid selectivity (as high as 17% and 16%, respectively), and the yield to methacrolein
and methacrylic acid reached 3.6% and 3.5%, respectively, at 21.3% isobutane conversion at 440°C. 相似文献