Design and construction of metalloproteins/bilayer film devices and their application

本课题“金属蛋白/双层膜器件的设计与构建及其应用”的研究成果总结如下。合成了双长链二茂铁2C16GluFc，研究了二茂铁脂膜固定化葡萄糖氧化酶介导的电子转移反应。用2CI6GluFc和合成脂质二十六烷基二甲基溴化铵（2C16N^+Br^-）修饰的石墨（BPG）电极得到了相变相关的循环伏安图。常规脉冲伏安法证明了在相变温度以上电极处法拉第电流的增强是由于表观扩散速率常数的增加。将葡萄糖氧化酶固定在BPG上的2C16GluFc/2C16N^+Br^-膜上，探讨了葡萄糖存在下二茂铁介导的催化电子转移。温度实验表明，相变对催化电子转移反应起调节作用。在四种人工脂铵膜中包埋的铁氧还蛋白[2Fe-2S]簇结构的热稳定性比在溶液中包埋的铁氧还蛋白的热稳定性要好得多。人工阳离子铵盐脂质膜为铁氧还蛋白的掺入提供了合适的微环境，从而与底层电极进行电化学通信。我们首次证明，在人工脂质2C18N^+Br^-的铸膜中，铁氧还蛋白的扩散常数D和非均相电子转移速率常数k^0'分别为4 X 10^-^1^0 cm^2 s^-^1和1.4 X 10^-^4 cm s^-^1。膜中铁氧还蛋白的D和k^0′值与2C18N^+r^-膜中铁氧还蛋白的D和k^0′值接近。实验观察到的铁氧还蛋白在薄膜中的伏安图与利用所得的D和k^0′模拟的伏安图吻合良好。

Results of our research project titled on Design and construction of metalloproteins/bilayer film devices and their application are summarized as follows.1. A ferrocene with double long chains, 2C16GluFc, was synthesized and regulated mediated electron transfer reactions of glucose oxidase immobilized on a lipid film containing ferrocene was examined. A graphite (BPG) electrode modified with a cast of 2CI6GluFc and a synthetic lipid, dihexadecyldimethylammonium bromide (2C16N^+Br^-) gave phase transition dependent cyclic voltammograms. Normal pulse voltammetry proved that the enhancement of the faradaic current at the electrode at temperatures above the phase transition is ascribable to the increase in the apparent diffusion rate constants. Glucose oxidase was immobilized on the film of 2C16GluFc/2C16N^+Br^- on BPG and ferrocene-mediated catalytic electron transfers in the presence of glucose were explored. Temperature experiment has revealed that the phase transition regulates the catalytic electron transfer reaction.2. Thermal stability of the [2Fe-2S] cluster structure of ferredoxin embedded in the films of four artificial ammonium lipid was much improved than that of ferredoxin in solution. Artificial cationic ammonium lipid films were found to provide suitable microenvironments for the incorporation of ferredoxin in a way to undergo electrochemical communication with the underlying electrodes. We have demonstrated for the first time that the diffusion constant, D, and the heterogeneous electron transfer rate constant, k^0', for ferredoxin embedded in a cast film of an artificial lipid, 2C18N^+Br^-, are 4 X 10^-^1^0 cm^2 s^-^1 and 1.4 X 10^-^4 cm s^-^1, respectively. D and k^0' values of ferredoxin in the films of the films were close with those of ferredoxin in 2C18N^+r^- films. The experimentally observed voltammograms of ferredoxin in the film fitted well with the simulated voltammograms using the obtained D and k^0'.