聚苯胺用作乙醇脱氢反应中的电子传递介质

脱氢酶（ADH）在电化学氧化还原反应中是很重要的一种酶，但它在催化有机分子脱氢反应时需烟酰胺腺嘌呤二核苷酸（NAD＋）参与，后者从底物接收电子生成还原形NADH.脱氢酶电极是根据NADH的电化学氧化产生的阳极电流构成的1－3].然而NADH与裸体炭电极和铂金电极之间的直接电子传递是非常困难的，往往需一个相当高的过电位4].另一个问题是生成物易将电极玷污5，6].克服这些问题的方法是使用均相电子传递介质，例如在底物溶液中加入Meldola蓝、Nile蓝A和NMP＋甲替硫酸盐等7－9]，及复相电子传递介质，例如将镍六氰基高铁酸盐固…

Polyaniline Used as An Electron Transfer Mediator for the Catalyzed Dehydrogenating Reaction of Alcohol

The aniline solution containing nicotinamide adenine dinucleotide(NAD＋ )was electrolyzed. Polyaniline film with NAD＋ formed on the platinum thin plate. The thickness of the film was controlled by the charge consumed in the electrolysis, which was 0.006 C in this case. This electrode, used as an anode, was immersed in the solution containing aniline. A second film formed on this electrode during the electrolysis. The charge passed during the second electrolysis was 0.016 C. Alcohol dehydrogenase(ADH) was immobilized on the polyaniline film based on the isoelectric point of ADH and the doping principle of conducting polymers. The enzyme electrode has a good bioelectrochemical response to ethanol in the absence of a homogeneous mediator. The optimum pH, apparent Michaelis- Menten constant and optimum temperature of ADH immobilized in polyaniline film are 7.83, 7.5 mmol? dm－ 3, and 30.6 ℃ , respectively. The activation energy of the enzyme- catalyzed reaction is 33.5 kJ? mol－ 1. The response current of the enzyme electrode increases linearly with increasing concentration of ethanol below 2.4 mmol? dm－ 3.This enzyme electrode can be used to determine the concentration of ethanol.