Fabrication and Evaluation of Functional Lipid Bilayer Membranes which oxidize NADH.

1.黄递酶固定化表面NAD(H)的再生黄递酶通过与氨基乙硫醇和戊二醛分步反应固定在金电极上。表面浓度为6×10~(-12)mol/cm~2。以二茂铁基甲醇(FMA)为媒介的循环伏安法表明，NADH存在时，FMA的氧化峰显著增加。根据起始电流区1/i-exp[F(E-E)/RT]图的截距和斜率，确定米氏常数和分子活度分别为8×10^&lt；-7&gt；M和k2=9s^-lt；-1&gt；2.用电化学方法研究了含四氰基喹二甲烷(TCNQ)的平面型双层类脂膜(BLM)的电子传输和带有阿维菌素离子通道的BLM的离子传输.从BLM的阻抗谱确定了氧化还原物种与BLM之间的非均相电子转移速率。结果表明，疏水作用和静电作用在电子转移过程中起着重要作用。通过测量I^-在BLM附近的微盘电极上的氧化电流，研究了I^-通过阿霉菌素通道的选择性测定。通过对膜电位作用下氧化电流的分析，确定了I^-通过膜的通量。

1.Regeneration of NAD(H) at Diaphorase-Immobilized SurfacesDiaphorase was immobilized onto an Au electrode by step-by-step reaction with aminoethanethiol and glutaraldehyde. The surface concentration was found to be 6x10^<-12> mol/cm^2. Cyclic voltammetry with ferrocenylmethanol (FMA) as mediator showed a remarkable increase in the oxidation peak for FMA in the presence of NADH in solution. From the intercept and slope of the 1/i vs. exp[F(E-E)/RT] plot at the onset current region, the Michaelis constant and the molecular activity have been determined, respectively, to be 8x10^<-7> M and k_2=9s^<-1>.2.Ion-and Electron-Transport Across a Planer Bilayer Lipid Membrane (BLM)The electron-transport across the BLM containing tetracyanoquinodimethane(TCNQ) and the ion transport through the BLM with alamethicin ion channels were investigated by electrochemical methods. From the impedance spectroscopy of the BLM, heterogeneous electron-transfer rates between redox species and the BLM were determined. The results demonstrated that hydrophobic and electrostatic interactions have important roles in the electron-transfer. The selective determination of I^- transported through alamethicin channels was also investigated by measuring the oxidation current of I^- at a microdisk electrode located near the BLM. From the analysis of the oxidation current upon application of membrane potential, the flux of I^- through the BLM was determined.