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

1.心肌黄酶固定化表面再生NAD（H）的研究心肌黄酶以氨基乙醇和戊二醛分步固定在Au电极上。发现表面浓度为6x 10 ^<-12>mol/cm ^2。以二茂铁甲醇（FMA）为介体的循环伏安法表明，溶液中存在NADH时，FMA的氧化峰显著增加。由1/i vs. exp[F（E-E）/RT]曲线在起始电流区的截距和斜率确定了米氏常数为8 × 10 ~（-1）M，分子活性<-7>为k_2= 9 s ~（<-1>-1）。用电化学方法研究了丙甲霉素离子通道对BLM离子转运的影响。从阻抗谱的BLM，氧化还原物种和BLM之间的异质电子转移速率进行了测定。结果表明，疏水相互作用和静电相互作用在电子转移过程中起重要作用。通过测量I^-在位于BLM附近的微盘电极上的氧化电流，还研究了通过丙甲霉素通道转运的I^-的选择性测定。通过分析施加膜电位时的氧化电流，可以确定I^-通过BLM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.