The effect of structure of the enzyme-fixed polymers on the reactivity of enzyme

固定化酶被认为是一种改性酶，在生物反应器和传感器等领域有着广泛的应用。Nelson和Griffins观察到非均相溶液形式的酶的反应性。关于修饰酶，尤其是传感器的研究论文很多。摘要本研究的目的是阐明膜中含铜聚合物对固定化抗坏血酸氧化酶（ASOD）反应活性的影响及其与膜电位的关系。ASOD是一种特殊的含铜酶。本文首先制备了具有n -甲基- n -羧甲基二硫代氨基甲酸酯的聚氯乙烯，该聚氯乙烯能形成螯合络合物，并将其作为结合ASOD的聚合物。将加入ASOD的溶液制成薄膜。然后铜被压入…更多地渗进膜中。氧电极系统与制备的膜相结合。用氧电极测定了电流的还原。得到了l -抗坏血酸浓度与电流减小的关系。然而，含铜螯合聚合物的电流还原不如非螯合聚合物高。认为膜内的交联使溶胀减小，氧扩散率降低。相反，使用成盐聚合物，如共聚物（甲基丙烯酸甲酯-丙烯酸），电流降低幅度更大。这一现象表明，膜的水化作用和铜的存在增强了传感器的响应。采用自旋壳体法在多孔聚丙烯薄膜表面制备了氯甲基化聚- γ -甲基- l-谷氨酸薄膜，并用三甲基胺进行了季铵化。用同样的方法固定ASOD。这种类型的传感器被发现在灵敏度和耐用性方面都很好。利用新的膜电位理论分析了酶固定复合膜的响应与膜电位变化的关系。少

Immobilized enzymes are considered to be a kind of modified enzymes and used in the fields of bioreactors and sensors. The reactivity of enzymes which is not in the form of their homogeneous solutions was observed by Nelson and Griffins. There have been lots of papers concerning modified enzymes, especially sensors. The objective of this study is to clarify the effect of polymers which have copper in membranes on the reactivity of immobilized ascorbic acid oxidlse (ASOD), because ASOD is a special enzyme containing copper and the relationships between the function and the membrane potential. The sensor which has ASOD in the membrane are now used in order to know the concentration of ascorbic acid in raw fishes or Vitamin C.At first, poly (vinyl chloride) having N-methyl-N-carboxymethyl dithiocarbamate which is able to form a chelate complex, was prepared and used as a polymer for combining ASOD. A thin membrane was casted from the solution to which ASOD was added. Then copper was impre … More gnated into the membrane. Oxygen electrode system was combined with membranes prepared. A current reduction was measured by oxygen electrode. The relationships between the concentration of L-ascorbic acid and the decrease of the electric current, were obtained. However, the current reduction of the copper-containing chelate polymer, was not so high as that of non-chelate polymer. It is considered that crosslinking in the membrane caused the decrease of the swelling and reduced oxygen diffusivity. In stead, using salt-forming polymers such as copoly (methyl methacrylate-acrilic acid) gave the higher decrease of the electric current. This phenomena suggest that both hydration of the membrane and the presence of copper enhanced the response of the sensor.Thin membranes of Chloromethylated polymay-gamma-methyl-L-glutamate were prepared on the surface of a porous polypropyrene sheet by the spin-caseted method and quariernized with trimthylamine. ASOD was fixed by the identical way. This type of the sensor was found to be excellent in both sensitivity and durability.Also, the relationships between response of the enzyme-fixed composite membranes and their change of the membrane potential was obtained and analyzed with our new membrane potential theory. Less