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辣根过氧化物酶/聚邻苯二胺膜电极的制备与性能研究 总被引:5,自引:0,他引:5
辣根过氧化物酶(HRP)/聚邻苯二胺(PPD)膜电极由pH7.0磷酸盐缓冲溶液介质中邻苯二胺在玻碳电极上的电聚合而制得。讨论了HRP电化学固定化的过程。所得酶电极呈现生物催化活性,可以没有电子传递体存在的情况下催化H2O2还原。该反应发生在聚邻苯二胺氧化还原的电位区,聚合物参与了酶的电子转移过程。分析了旋转HRP/PPD电极上酶反应的动力学,讨论了动力学常数的影响因素。 相似文献
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利用电化学固定化方法制备了聚吡咯/辣根过氧化物酶(PP/HRP)膜电极,并研究了其电化学行为,在除氧的磷酸盐缓冲液介质中,PP/HRP电极加速H2O2的还原,归因子酶加成物的直接电子传递,探索HRP与电子传递体K4Fe(CN)6在聚吡咯(PP)膜中的同时固定化条件及其膜电极的电化学行为,实验证实,K4Fe(CN)6在酶膜中的存在使得H2O2的还原电位强烈正移,在-0.05V的工作电位下能对H2O2 相似文献
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辣根过氧化物酶的电化学固定化及其对H_2O_2的生物电催化还原作用 总被引:6,自引:0,他引:6
利用电化学固定化方法制备了聚吡咯/辣根过氧化物酶(PP/HRP)膜电极,并研究了其电化学行为。在除氧的磷酸盐缓冲液介质中,PP/HRP电极加速H_2O_2的还原,归因于酶加成物的直接电子传递。探索HRP与电子传递体K4Fe(CN)6在聚吡咯(PP)膜中的同时固定化条件及其膜电极的电化学行为,实验证实,K_4Fe(CN)_6在酶膜中的存在使得H_2O_2的还原电位强烈正移,在-0.05V的工作电位下能对H_2O_2进行检测,相应的电极过程可用间接氧化还原催化机理解释。 相似文献
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金电极表面聚赖氨酸固定微过氧化物酶-11的电化学研究 总被引:1,自引:0,他引:1
通过聚赖氨酸修饰将微过氧化物酶-11(MP—11)固定在金电极表面,制备成MP-11修饰电极.修饰在电极表面上的MP-11的血红素活性中心与电极之问可进行直接的电子传递反应,其氧化还原式电位为-0.39V.该修饰电极对氧的还原具有电催化活性.当MP-11与咪唑发生轴向配位反应时,其氧化还原式电位发生负移,此时对氧的还原不再具有电催化活性. 相似文献
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以二环己基碳化二亚胺为活化剂将葡萄糖氧化酶(GOD)共价键接在玻碳电极上, 伏安实验观察到酶与电极基体的直接电子传递, 有观电子传递速度常数约为1s^-^1, 过程归因于全酶中辅基FAD的氧化还原转变。Ag^+离子的存在强烈地阻碍酶辅基的还原, 这与该离子抑制酶活性的机理可能有联系。Ag^+的抑制作用可由EDTA处理或电化学处理而解除, GOD电极对氧和苯醌的电还原有催化作用。测定了苯醌同还原态GOD的化学反应速度常数, 并讨论用苯醌代替氧作为生物电催化中的电子传递体的优点。 相似文献
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聚吡咯电化学固定化胆固醇氧化酶电极的电流响应及应用 总被引:1,自引:0,他引:1
用电极法测定总胆固醇量,可以通过制备胆固醇氧化酶和胆固醇脂酶的酶膜与氧电极偶联制成传感器或制备以过氧化氢检出方式的传感器来完成,本文研制了一种新型的酶电极,它不需选择电荷传递中间体代替氧分子的作用,本方法利用吡咯单体在水溶液中能电氧化聚合,并伴有对阴离子嵌入聚合物骨架的性质,使酶分子在聚合过程中作为阴离子而嵌 相似文献
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《Electroanalysis》2005,17(24):2239-2245
The characteristics of a multiuse planar amperometric biosensor modified with Nafion and/or polyion membrane were investigated. A new enzyme immobilization process was proposed, in which the polyvinyl alcohol bearing a styrylpyridinium (SbQ)/glucose oxidase composite was treated with glutaraldehyde vapor prior to the photocrosslinking reaction. The resulting planar enzyme electrode remains active for at least 150 days. Compared with poly‐L ‐lysine/poly (4‐stryenesulfonate) polyion complex membrane the Nafion membrane showed marked effect to reduce the electrochemical response of the modified planar enzyme electrode to the biological interferents, such as ascorbic acid and uric acid. Furthermore, Nafion membrane can effective restricting the oxidized anionic interferent to adhear on its surface, thereby the fouling of the electrode was avoided. 相似文献
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《Electroanalysis》2002,14(23):1644-1647
The activity of urease varies by its redox reaction. Active urease has an SH group that is essential to exhibit its activity, however, oxidation agents such as quinone compounds can oxidize the SH group in urease and a S–S bond is produced, resulting in the loss of enzyme activity. The reduction potential of cystine was almost the same as that of the recovery of urease activity. In this work, it has been found that the SH group of urease can be oxidized by not only chemical reaction but also by the direct electrode oxidation of urease and the produced S–S bond can be reduced to SH group by chemical and electrode reactions, and the original enzyme activity is recovered. This research shows that the regulation of urease activity is easily possible by changing the electrode potential of the porous carbon felt immobilized urease. The variation of urease activity was monitored by ammonia or carbon dioxide electrode equipped with the urease immobilized carbon felt, and the ammonia or carbon oxide generated from urea can transfer through the carbon felt to reach the each gas permeable membrane. The combination of gas electrode with porous conducting material such as carbon can supply the novel device for the electrochemical investigation of enzyme activity. 相似文献
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Kumi Inoue Pascal Ferrante Yu Hirano Tomoyuki Yasukawa Hitoshi Shiku Tomokazu Matsue 《Talanta》2007,73(5):886-892
An immunochromatographic assay using nitrocellulose membrane was combined with electrochemical detection using an electrode chip in order to quantitatively detect testosterone as a model analyte. The electrode chip consisted of a gold working electrode, a counter electrode and a pseudo-reference electrode, all fabricated on the bottom of a 3.2 mm × 3.2 mm well. Competitive immunoreactions on the membrane were initiated by flowing a solution containing testosterone and horseradish peroxidase (HRP)-labeled testosterone (a competitor) over the membrane. Prepared membrane was placed in a solution containing ferrocenemethanol (FcOH) and H2O2 in the well of the electrode chip, and the enzyme reaction was detected by amperometry. Labeled HRP captured on the membrane catalyzed the oxidation of FcOH to the oxidized form FcOH+, which was reduced electrochemically by the electrode chip. The electrochemical response of the reduction current decreased with increasing concentration of testosterone over the range 1–625 ng/ml. 相似文献
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Laurinavicius V Kurtinaitien B Liauksminas V Jankauskait A Simkus R Meskys R Boguslavsky L Skotheim T Tanenbaum S 《Talanta》2000,52(3):485-493
Partially hydrolyzed polyarbutin-containing benzoquinone groups were synthesized by using chemoenzymatic methods. This polymer was used as a mediator for the oxidation of pyrroloquinoline quinone-dependent glucose dehydrogenase. Polymer was covalently attached to the enzyme through the glucose moiety of the polymer and amine residues in the protein. Electrochemical studies show that the oxidized benzoquinone attached to the enzyme can act as a mediator for the reoxidation of the enzyme at carbon electrode surfaces. The apparent Michaelis constant and inactivation rate constant of the coupled enzyme were found to be similar to these parameters of the native enzyme. 相似文献
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A novel method for preparing enzyme membranes was developed. The enzyme was attached onto the electrode surface by dropping the enzyme solution and allowing it to dry. Glucose oxidase was used for entrapment. Then, the electrode surface was coated with an ionic liquid containing cellulose, and the ionic liquid was removed by immersing the electrode into water. Enzyme activity was retained in the membrane; the enzyme electrode can be used for detecting glucose in the range of 10 μM to 1 mM, and the response time was ~10 s. The stability duration of the electrode was examined: the enzyme electrode could be used for glucose detection for 6 months. The membrane was observed by atomic force microscopy in the force modulation mode; crystalline and amorphous parts were intermingled. In conclusion, the cellulose membrane can be a suitable immobilization matrix for enzymes. 相似文献
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The construction and response of an immobilized enzyme modified electrode as an amperometric sensor is described. Xanthine oxidase was adsorbed on a carbon paste electrode and physically entrapped with a semipermeable membrane. Uric acid, the product of the enzymatic reaction, was oxidized electrochemically at +0.4 V vs. Ag/AgCl, yielding a steady-state current directly related to the bulk concentration of the substrate. Hypoxanthine and xanthine were determined in the range 5–100 μM at Ph 7.2 with good precision. Interferences are discussed. 相似文献
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《Electroanalysis》2006,18(1):95-102
A novel ultra thin polydivinylbenzene/ethylvinylbenzene composite membrane has been developed for use as the outer covering barrier in a model amperometric glucose oxidase enzyme electrode. The composite membrane was formed via the cathodic electropolymerization of divinylbenzene/ethylvinylbenzene at the surface of gold sputter coated host alumina membranes, (serving solely as a mechanical support for the thin polymer film). Permeability coefficients were determined for the enzyme substrates, O2 and glucose, across composite membranes formed with a range of polymer thicknesses. Due to the highly substrate diffusion limiting nature of the composite membrane, it was found that anionic interferents present in blood (such as ascorbate), were effectively screened from the working electrode via a charge exclusion mechanism, in a manner similar to previous findings within our laboratory. The enzyme electrode showed an initial 32% signal drift when first exposed to whole human blood over a period of 2 hours, after which time enzyme electrode responses remained essentially stable. Whole blood patient glucose determinations yielded a correlation coefficient of r2=0.97 in comparison to standard hospital analyses. 相似文献
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Specific analytical problems often arise which can be easily solved if a mercury electrode of constant surface area is used as voltammetric sensor. In this work a membrane covered mercury electrode was prepared and used in solving various analytical tasks. One of them was the determination of water hardness. A sample injection method was developed applying EDTA reagent and a flow-through analytical system. Two different voltammetric enzyme electrodes (measuring glucose and L-amino acid) were prepared by using the membrane covered mercury electrode as base sensor. The application of the enzyme electrode in flow-through circumstances was proved to be very advantageous in determining selectively L-DOPA in the presence of the D-form. 相似文献
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Tokuji Ikeda Takashi Shibata Setsuko Todoriki Mitsugi Senda Hideaki Kinoshita 《Analytica chimica acta》1990
A mediated amperometric enzyme electrode, which was constructed by immobilizing oligosacharide dehydrogenase behind a dialysis membrane on the surface of a carbon paste electrode containing p-benzoquinone, showed a current response to d-xylose, d-galactose, d-mannose, lactose, maltose, maltotriose, maltopentaose and maltohexaose. The sensitivity of the current response to these carbohydrates was dependent on the kinetics of the immobilized enzyme reaction and/or the permeation rate of the substrate through the dialysis membrane. Hence the sensitivity could be varied by controlling the amount of the immobilized enzyme and the thickness of the dialysis membrane. The time dependence of the current response ofthe enzyme electrode with a large amount of the immobilized enzyme and a thicker dialysis membrane could be explained by an equation describing diffusion of the substrate in the membrane. The enzyme electrode was used to measure lactose in milk and to assay α-amylase in standard serum. 相似文献