利用流动注射型乙酰胆碱酯酶传感器监测海水中马拉硫磷

将乙酰胆碱酯酶(AChE)传感器引入流动注射系统中，研究了传感器连续监测海水中马拉硫磷的可行性。系统中的载液为不含马拉硫磷的海水。传感器适宜的工作条件为：载液和样品的流速为0．39mL／min，进样时间为20min；底物(碘化硫代乙酰胆碱)溶液的浓度为41．6mmol／L，注射量为40μL。利用次氯酸钠溶液对含马拉硫磷的海水样品进行预氧化处理，可以大大提高传感器的灵敏度，对马拉硫磷的检出限达到0．05μg/L；而不进行氧化时的检出限为1．3μg/L。另外，海水样品经过预氧化处理后，传感器对其中0．1-10μg／L的马拉硫磷具有良好的线性响应关系(r=0．991)。测定含马拉硫磷的海水样品后，向传感器持续通入0．5mmol／L的2-PAM溶液15min，可以完全恢复受到100μg／L马拉硫磷抑制的固定化酶活性。结果表明：所设计的酶传感器适于海水中马拉硫磷的连续、灵敏和准确监测。     

Spectrophotomeric Assay of Aflatoxin B1 Using Acetylcholinesterase Immobilized on Standard Microplates

Aflatoxins are a group of hepatotoxic secondary metabolites produced by molds Aspergillus. During inappropriate storage or processing of food and beverages, aflatoxins can be distributed and become a serious health problem. Disparate analytical techniques were prepared for the assay in the past. Here, a method based on inhibition of enzyme acetylcholinesterase (AChE) is performed allowing fast and simple prove of aflatoxins presence. For the assay purposes, AChE was immobilized on standard polystyrene microplates using gelatin as a stabilizing substance. Both free and immobilized AChEs were used and compared one to each other. Immobilization protocol was optimized and interference of organic solvents such as methanol was tested. For the immobilized AChE, limit of detection 2.75 ppb for aflatoxin B1 was received. The immobilized AChE kept full activity at least one month. Suitability of the assay for a practical performance is considered.     

多壁碳纳米管修饰酶电极测定马拉硫磷

应用化学交联法将巴西日圆线虫乙酰胆碱酯酶(AChE)固定于多壁碳纳米管修饰的玻碳电极表面,制备用于有机磷农药检测的电化学生物传感器.研究了巯基胆碱(TCh)在该修饰电极上的电化学行为.优化实验条件得出,响应电流与马拉硫磷的浓度在6.0×10-10~6.0×10-9mol.L-1范围内呈良好的线性关系,检出限为1.0×10-10mol.L-1.测定了湖水中马拉硫磷的含量,回收率为97%~105%.     

固定化乙酰胆碱酯酶的制备及其特性研究

本研究以期研制出能重复使用的固定化乙酰胆碱酯酶(AChE),为天然产物复杂体系中AchE抑制剂筛选新方法的发展奠定基础.以氨基化硅胶(APS-Si)微球为载体,戊二醛为交联剂对乙酰胆碱酯酶进行交联固定化,并研究了酶的最佳固定化条件和固定化酶的性质.结果表明,0.05 g氨基化硅胶微球载体,用戊二醛溶液活化6 h后,在给酶量5 U,28℃固定16 h条件下,得到固定化酶的活性最大.固定化酶在常温(20～40℃),以及较宽pH范围内(pH 6～10)均具有较高的活性,并且具有良好的保存稳定性和可重复利用率,为基于固定化靶酶亲和-色谱质谱联用分析快速筛选乙酰胆碱酯酶抑制剂新方法的发展奠定了基础.     

再生丝素固定乙酰胆碱酯酶生物传感器

再生丝素固定乙酰胆碱酯酶生物传感器;生物传感器;乙酰胆碱酯酶;再生丝素     

A Biotest Based on an Acetylcholinesterase Tissue Preparation Immobilized on Paper

A sensitive biotest for determining acetylcholinesterase inhibitors has been developed on the basis of a paper matrix and an electric eel (Electrophorus electricus) tissue preparation with high enzymatic activity. Photometric detection at λ = 480 nm based on the ferricyanide reaction (resulting in the formation of copper ferricyanide) was used. The biotest allows the determination of carbamate inhibitors (eserine and neostigmine) and sanguinarine (an isoquinoline alkaloid) at levels of 10^?6 to 10^?5 M.     

Stabilization of Dry Immobilized Acetylcholinesterase on Nitrocellulose Membrane for Rapid Colorimetric Screening of Its Inhibitors in Water and Biological Fluids.

Abstract

We show the ability of a gelatin and a BSA-trehalose film to convert normally fragile dry immobilized acetylcholinesterase enzyme (AchE) into a stable reagent on nitrocellulose membrane. The remarkable property of the dry immobilized AchE enzyme preparation is its stability when exposed to temperatures as high as 50°C. The proposed method offers a rapid, simple, and inexpensive means in a non-laboratory setup for qualitative analytical colorimetric screening of AchE inhibitor residues such as pesticides and drugs in water and biological fluids.     

KDNBF形貌控制及其对热分解行为和感度的影响(英文)

通过7-羟基-4,6-二硝基-5,7-二氢苯并呋咱(DNBF)的钠盐与硫酸钾在水溶液中反应,制备得到DNBF的钾盐(KDNBF).在制备过程中加入不同表面活性剂,得到了不同晶形的KDNBF样品.运用X射线粉末衍射分析了单种晶形控制剂对样品晶形的影响.采用差示扫描量热(DSC)和热重(TG)分析技术研究了不同晶形样品的热分解特性,利用Kissinger方法和Ozawa-Doyle方法研究了样品第一放热分解峰的分解动力学过程.结果表明球形样品与其它晶形的样品相比,具有较低的分解温度、较高的活化能;同时发现,球形样品具有较高的摩擦和撞击感度与较低的火焰感度.     

基于功能化石墨烯-聚乙烯醇复合膜固定乙酰胆碱酯酶的甲拌磷传感器

将功能化离子液体修饰石墨烯(IL-GR)分散在聚乙烯醇(PVA)中,制得IL-GR-PVA分散液,与乙酰胆碱酯酶(ACh E)溶液混匀后滴涂在电极表面,利用PVA良好的成膜特性,制得新型有机磷检测酶电极ACh E/IL-GR-PVA/GCE,并用于有机磷农药的检测。采用透射电镜(TEM)表征了IL-GR的形貌,采用循环伏安法(CV)和差示脉冲伏安法(DPV)研究了酶电极的电化学性质。结果表明,IL-GR-PVA复合膜具有良好的导电性和生物相容性,能很好地保持ACh E的生物活性,并显著促进了其电化学过程。在优化实验条件下,抑制率(I%)与甲拌磷浓度的负对数在1.0×10-14~1.0×10-9mol/L和1.0×10-9~1.0×10-6mol/L范围内呈良好的线性关系,检出限(S/N=3)为8.0×10-15mol/L。该传感器制备简单,稳定性好,灵敏度高,为有机磷农药的测定提供了新方法。     

基于修饰石墨烯/纳米金复合膜固定乙酰胆碱酯酶的敌百虫传感器

结合氨基功能化离子液体修饰石墨烯(IL-GR)、纳米金(Au)等纳米材料的独特性质,以壳聚糖(CHIT)为交联剂,首先在玻碳电极表面固定IL-GR,然后吸附胶体金制得Au/IL-GR-CHIT复合膜,最后固定乙酰胆碱酯酶(AChE)制得新型有机磷检测酶传感器(AChE/Au/IL-GR-CHIT/GCE),并用于白菜样品中敌百虫农药的测定。采用透射电镜(TEM)对纳米材料进行了表征,循环伏安法(CV)和差示脉冲伏安法(DPV)研究了传感器的电化学性质。纳米复合物不仅为保持AChE的生物活性提供了适宜的微环境,并且对传感器性能的改善显示出强大的协同效应。在优化实验条件下,抑制率(A)与敌百虫浓度的负对数在2.0×10-10~1.0×10-6mol/L范围内呈良好的线性关系,检出限(S/N=3)为2.1×10-12mol/L。用于蔬菜中敌百虫含量的测定,回收率为97.5%~107.2%。     

Resolution of Ibuprofen Catalyzed with Free and Immobilized Lipases

Enzymatic hydrolyses of ibuprofen esters produced 99% optically pure S-(+)-ibuprofen. The ee values of two enantiomers of ibuprofen were determined on a HPLC equipped with a chiral column.     

基于固定化酶的乙酰胆碱酯酶抑制剂体外筛选模型的建立

以可重复使用的固定化酶代替游离态酶, 建立一种基于比色分析的乙酰胆碱酯酶(AChE)抑制剂体外筛选新模型. 采用以氨基化硅胶为载体固定的AChE优化了实验条件, 用AChE抑制剂阳性对照物他克林和毒扁豆碱对该模型进行验证, 还对模型技术参数进行评价, 并将新模型用于单体化合物及天然产物粗提物AChE抑制活性评价. 结果表明, 最佳实验条件为: 固定化酶用量55 μL, 底物浓度5 mmol/L, 甲醇、 乙醇及体积分数不高于6%的二甲基亚砜水溶液均可作为样品溶剂; 模型验证及模型技术参数评价结果良好, 该模型对AChE抑制剂筛选有较好的特异性和灵敏度, 可用于筛选AChE抑制剂. 该模型具有适用性强、 固定化酶可重复使用及结果可靠等优点, 是单体化合物及天然产物粗提物AChE抑制剂活性评价的有效方法.     

Quantitative Separation of Tetralin Hydroperoxide from Its Decomposition Products by High Performance Liquid Chromatography

Abstract

A method for the separation and analysis of tetralin hydroperoxide and its decomposition products by high pressure liquid chromatography has been developed. Elution with a single, mixed solvent from a μ-Porasil column was employed. Constant response factors (internal standard method) over large concentration ranges and reproducible retention parameters are reported.     

漆树酶固定化及其性质研究

本文介绍了用过渡金属水合氧化物固定化漆树漆酶的方法。考察了整合法固定漆树酶的最适条件。对固定化前后漆酶的性质进行了比较,并分析了造成固定化酶与游离酶性质差异的原因。     

The Influence of Inorganic Salts on the Inhibition of Acetylcholinesterase by O,O-Diethylthiophosphates

Abstract

The influence of various inorganic salts (NaCl, KCl, CsCl, KNO₃, Na₂SO₄, K₂SO₄, MgCl₂, CaCl₂) on the kinetics of the reactions of acetylcholinesterase with neutral and cationic 0,O-diethylthiophosphates, (C₂H₅0)₂ P(0)SX, where × = (CH₂)_n and (CH₂)_n S⁺ (CH₃) C₂H₅ (n=1–6), has been studied at 25° C and pH 7.5. The salt effect in the second-order rate constant can be quantitatively described by the equation log(k₂/K_s) = log(k₂ /K_S)°-ψlog[M] + bc where bc is the term for the kinetic salting effect, ψlog[M] is the electrostatic term, c and [MI are the molar concentrations of salt and salt cation. The salting effect is observed in the binding step (K_s) as well as in the enzyme phosphorylation step (k₂). Parallel increase of b with increasing n has been observed for the series of both ionic and neutral inhibitors. Electrostatic effect is observed only in the binding step for cationic inhibitors and does not depend on the distance between the onium atom and the reaction center in the inhibitor molecule. The observation of uniform Y is in accordance with the Manning's polyelectrolyte theory, suggesting that acetylcholinesterase can be considered as negatively charged polyelectrolyte. According to the theory the release of condensed counterions from the polyelectrolyte provides electrostatic contribution to the binding of cationic ligands, and the presence of localized anionic site on the acetylcholinesterase molecule is not required to account for the observed electrostatic effect. The obtained mean value of ψ = 0.49 ± 0.08 can be used as a quantitative parameter to characterize the effective charge density of acetylcholinesterase.     

MgCO3.3H2O水热分解产物及其组成

ＭｇＣＯ_３·３Ｈ_２Ｏ水热分解产物及其组成翟学良，周相廷，李美玲（河北师范大学化学系石家庄０５００１６）关键词ＭｇＣＯ_３·３Ｈ_２Ｏ，Ｍｇ_５（ＣＯ_３）_４（ＯＨ）_２·８Ｈ_２Ｏ，Ｍｇ_５（ＣＯ_３）_４（ＯＨ）_２·５Ｈ_２Ｏ，水热分解，中间体ＭｇＣＯ_...     

游离和溶胶-凝胶固定化甲醛脱氢酶酶促反应动力学的研究

采用溶胶-凝胶法对甲醛脱氢酶进行固定化，酶的包埋率超过了98％．在pH7附近、37℃下，以游离酶和固定化酶作催化剂，NADH为电子供体，进行了甲酸转化为甲醛的酶促反应．游离和固定化甲醛脱氢酶酶促反应都遵循Michaelis-Menten反应机理，用Dalziel提出的双底物酶促反应动力学方程进行拟合．固定化酶酶促反应速率为游离酶酶促反应速率的50％左右．固定化酶的动力学常数φ和米氏常数K高于游离酶，估计是凝胶基质孔中存在扩散效应所致．     

The Gas Chromatographic Determination of the Decomposition Products of Tributyl Phosphate

Abstract

The products formed from tributyl phosphate in different diluents have been quantitatively analyzed for components by gas chromatography. Methylation yields and limits of detection of di butyl phosphate are given.     

Electrochemical Assay of Methyl Parathion in Homogeneous Reaction Using Water Soluble Films with Immobilized Acetylcholinesterase

Water soluble poly (vinyl alcohol) (PVA) was used to prepare the enzyme membranes of acetylcholinesterase (AChE) for electrochemical assaying methyl parathion in water insoluble organic solvent. The immobilized enzyme was separated from electrode for the development of enzyme inhibition-based bioassays. This assay is simple and convenient where enzyme membrane is applicable for single use and the electrode for repeated use. The enzyme membranes can be used handily piece by piece and the released AChE performs catalytic reaction homogeneously. The inhibition percentage of AChE increases with the concentration of methyl parathion ranging from 0.1 to 1 mg/mL.     

AuNPs/Sol-gel复合膜法固定乙酰胆碱酯酶生物传感器检测有机磷农药

基于有机磷农药对乙酰胆碱酯酶(Acetylcholinesterase,AChE)的抑制作用,用金纳米粒子(Au nanoparticles,AuNPs)与壳聚糖/SiO2杂化溶胶-凝胶构成复合固酶基质,将AChE固定于玻碳电极表面,制备了电流型AChE生物传感器选用久效磷进行实验,以氯化硫代乙酰胆碱为底物,建立了电化...