吡啰红B为底物的氯化血红素催化荧光反应测定葡萄糖

吡红B在氯化血红素催化下可被过氧化氢氧化而使其荧光猝灭。在pH 5 .2弱酸性介质中 ,稳态催化速率由模拟酶和底物浓度决定 ,催化体系服从Michaelis Menten方程 ,用Lineweaver Burk作图法求得米氏常数 1.4× 10 - 5mol L ,最大反应速度 1.9× 10 - 6mol L·s ;催化常数 2 5 .6 /s。在最佳反应条件下 ,荧光猝灭程度F0 F与过氧化氢浓度在 0 .0～ 7.2× 10 - 7mol L范围内呈线性关系 ;检出限为 8.0× 10 - 9mol L。当与葡萄糖氧化酶联用时 ,可定量检测葡萄糖 ,线性关系为 (0 .0～ 1.0 )× 10 - 5mol L ;检出限为 3.3× 10 - 8mol L。方法用于分析人血清中葡萄糖含量 ,结果与苯酚 4 氨基安替比林法一致。     

氯化血红素的催化荧光测定

在碱性溶液中氯化血红素转化为高铁血红素，后者可催化过氧化氢氧化荧光供氢体反应，据此建立了氯化血红素的荧光测定方法。对测定条件包括缓冲溶液类型、酸度、荧光供氢体类型及过氧化氢和荧光供氢体的加入量等进行了考察，在０－３．５２μｇ／Ｌ范围内。     

氯化血红素的催化显色反应及分析应用

本文研究了以氯化血红素替代辣根过氧化物酶催化过氧化氢与4-氨基安替比林和苯酚的催化显色反应条件,拟订了测定过氧化氢的高灵敏催化分光光度法,做了多种离子对测定过氧化氢的干扰实验。并通过与葡萄糖氧化酶联用,拟订了水介质和血清中葡萄糖的分光光度测定方法,试用于测定血清样品中的葡萄糖含量得到了较满意的结果。     

胶束增敏的辣根过氧化物酶催化荧光反应测定葡萄糖的研究

采用葡萄糖氧化酶－辣根过氧化物酶－对羟基苯丙酸－过氧化体系测定葡萄糖，阳离子胶束十六烷基三甲基溴化铵对生荧反应具有催化和增敏作用，可用于１μ１样品中葡萄糖的测定，线性范围０．５－５０μｇ，线性相关系数ｒ＝０．９９６６，相对标准偏差为０．７３％，检测限为０．４６μｇ。     

无外加过氧化氢时氯化血红素催化性能的研究

研究了在十二烷基苯磺酸钠胶束介质中,氯化血红素对溶解氧氧化水杨基荧光酮的催化性能,发现该体系满足Ｍｉｃｈａｅｌｉｓ－Ｍｅｎｔｅｎ方程,在ｐＨ８．６的条件下,测得Ｋｍ和Ｖｍａｘ值分别为７．９４×１０＾－５ｍｏｌ／Ｌ和０．１１３ｓ＾－１。利用反应平衡法分光光度法可测定６．０×１０＾－８￣７．２×１０＾－７ｍｏｌ／Ｌ的Ｈｅｍｉｎ。     

氯化血红素催化反应体系的动力学性质及在葡萄糖分析中的应用

研究了氯化血红素作为过氧化物模拟酶催化显色体系（Ｃ６Ｈ５－ＯＨ－４－ＡＡＰ－Ｈ２Ｏ２）并与葡萄糖氧化反应介联的动力学性质。通过控制模拟酶和各反应物的用量确定了反应成假一级反应的葡萄糖浓度范围，在此反应体系中，葡萄糖浓度可以通过测定染料的吸光度而获得。该法干扰小，回收率达９４％￣９８％。检测限为２．０×１０＾－４ｇ／Ｌ。     

氯化血红素作为模拟酶荧光免疫分析乙肝表面抗原

乙肝表面抗原的测定在临床诊断上是一项很重要的指标．现在一般采用酶联吸附免疫分析技术测定，但是酶本身性质不稳定且价格昂贵、操作繁琐；更重要的是大分子的酶作为标记物，由于空间位阻效应而阻碍抗原-抗体的免疫反应．所以，用小分子催化剂代替大分子酶的研究显得日益重要[1，2]．近年来有关模拟酶在免疫分析中的应用已有报道[3，4]．本文提出了以氯化血红素作为辣根过氧化物酶（HRP）的模拟酶来标记抗体，以盐酸硫胺素（维生素B1）作为供氢体，成功地实现了乙肝表面抗原（HBsAg）的夹心法荧光免疫分析．测定范围是2．5～500ng／wel…     

氯化血红素的简便快速分离制备法

氯化血红素的简便快速分离制备法范俊源，罗一鸣，何顺华（湖南医科大学有机化学教研室，长沙４１００７８）氯化血红素（即１，３，５，８－四甲基－２，４－二乙烯基卟吩－６，７－二丙酸氯化铁），简称血红素。血红素是重要的生化试剂、食用色素、以及制备肝脏机能改善...     

氯化血红素催化氧化巯基形成二硫键

对氯化血红素催化氧化巯基形成二硫键的反应进行了研究,发现N,N-二异丙基乙胺(DIEA)的加入可以提高氯化血红素的催化活性,并降低其在氧化过程中的自聚现象.在室温及少量DIEA存在下,将氯化血红素和巯基乙酸甲酯按摩尔比1∶4混合于p H=8.0的水溶液中,敞口搅拌反应20 min,可以催化空气氧化90%的巯基乙酸甲酯形成相应的分子间二硫键产物.该催化氧化体系还可应用于多肽合成中,在相同条件下,只需2 h即可完成还原型催产素和利那洛肽的氧化环合,生成高产率的催产素和利那洛肽环肽.与传统的氧化方法相比,氯化血红素催化氧化的方法具有高效、环保的优点,为多肽合成中二硫键的形成提供了一种新方法.     

Hemin as a General Static Dark Quencher for Constructing Heme Oxygenase-1 Fluorescent Probes

The development of small-molecule probes suitable for live-cell applications remains challenging yet highly desirable. We report the first fluorescent probe, RBH, for imaging the heme oxygenase-1 (HO-1) activity in live cells after discovering hemin as a universal dark quencher. Hemin works via a static quenching mechanism and shows high quenching efficiency (>97 %) with fluorophores across a broad spectrum (λ_ex=400–700 nm). The favorable properties of RBH (e.g. long excitation/emission wavelengths, fast response rate and high magnitude of signal increase) enable its use for determining HO-1 activity in complex biological samples. As HO-1 is involved in regulating antioxidant defence, iron homeostasis and gasotransmitter carbon monoxide production, we expect RBH to be a powerful tool for dissecting its functions. Also, the discovery of hemin as a general static dark quencher provides a straightforward strategy for constructing novel fluorescent probes for diverse biological species.     

An Amperometric Glucose Electrode Based on Adsorbed Glucose Oxidase on Palladium/Gold Modified Graphite

Abstract

A glucose electrode was constructed by adsorbing glucose oxidase (GOD) on a modified electrode for H₂ O ₂ oxidation, consisting of Pd/Au sputtered on graphite. Maximally, 0.8 U cm^?2 of GOD could be adsorbed. The electrode was used in a f.i.a. manifold for determination of glucose. Linear calibration curves were obtained in the concentration range 3. 10^?6 4. 10^?3 mol L^?1 glucose. The applied potentials for glucose determination were + 300 mV vs. Ag/AgCl at pH 8.0, + 350 mV at pH 7.0, + 400 mV at pH 6.0 and + 500 mV at pH 5.0. The activity vs. pH profile of adsorbed GOD was broad having an optimum between pH 5 and 6. The apparent kinetic parameters for adsorbed GOD, K_M ^app and i_max, were found to be 50 mM and 160 uA at optimal pH.     

Flow-Injection Determination of Glucose by a Photoinduced Chemiluminescent Reaction

Abstract

A flow-injection procedure for the photochemical determination of glucose has been developed. The method is based on the photo-oxidation of glucose sensitized by 9,10-anthraquinone-2.6-disulfonate (disodium salt). The hydrogen peroxide formed in the photochemical reaction was measured by means of the chemiluminescent reaction with luminol and hematin. A linear calibration graph was obtained over the range 2.0x10^?6-8.5 x 10^?5 mol L^?1. The method was applied to determining glucose in blood serum, urine and fruit juices.     

轴向配基对HRP模拟酶Hemin催化荧光及化学发光反应影响的研究

以氯化血红素作为辣根过氧化物酶（ＨＲＰ）的模拟物,对二十种氨基酸和其他含氮有机配体的轴向配位效应进行了研究。发现在氯化血红素催化的荧光和化学发光体系中,组氨酸和咪唑均使ｈｅｍｉｎ的催化活性显著提高,而酪氨酸,色氨酸,Ｌ－半胱氨酸及卤代烷基吡啶等具有淬灭效应。     

Direct Determination of Glucose in Blood Serum Using Trinder's Reaction

Abstract

A very simple flow injection analysis system for direct determination of glucose in blood serum based on Trinder's reaction is described. The sera samples (15 μl) can be injected directly to the system without the deproteinization or the use of a dialyzer.

Calibration curves are linear in the range 50–400 mg/dl. The sampling frequency is 60 samples per hour. Results obtained by the proposed procedure are compared with those acquired at a local hospital using their routine glucose procedure also based on Trinder's reaction. It is shown that a better mix between sample and reagents is achieved using the single bead string reactor (SBSR).     

Flow-Injection Determination of Iron Based on Its Catalysis on the Oxidation Reaction of Xylenol Orange by Potassium Bromate

A flow injection system is proposed for catalytic kinetic spectrophotometric determination of trace iron(II + III). The involved reaction is based on the catalytic effect of iron(III) on oxidation reaction of xylenol orange by potassium bromate to form a blue-violet complex. Iron(II) is also determined, being oxidized to iron(III) by potassium bromate. The calibration graph is linear in the range of 0.02–10.0 µg l^?1 and 10.0–1100 µg l^?1. The relative standard deviation is 1.5% for 4.0 µg l^?1 iron(III) and 2.3% for 60.0µg l^?1 iron(III) (n = 11). The presented system was applied successfully to the determination of iron in natural waters.     

Flow Injection Analysis of Glucose in Human Serum by Chemiluminescence

Abstract

Combining the rigidly controlable conditions of Flow Injection Analysis with detection by chemiluminescence, a method for determination of glucose in serum via enzymatic degradation by glucose in serum via enzymatic degradation by glucose oxidase is described. With a Standard deviation of less than 2% the sampling frequency is 75 samples per hour. Results obtained by the proposed procedure are compared with those acquired by a routine AutoAnalyzer method used at a local hospital. It is shown that any influence on the yield of chemiluminescence due to difference in viscosity of the injected samples effectively can be eliminated.     

Amperometric Glucose Determination by Means of Glucose Oxidase Immobilized on a Cellulose Acetate Film: Dependence on the Immobilization Procedures

Glucose microelectrodes were prepared by immobilizing glucose oxidase onto a cellulose acetate film coating a platinum wire. Hexamethylenediamine (HMDA) and Glutaraldehyde (GA) were employed as spacer and coupling agent, respectively. Sensitivities and linear response ranges were studied as a function of the relative amounts of HMDA and GA. The best sensitivity was found when HMDA and GA were 5% and 2.5% in aqueous solutions, respectively. Taking as a reference the functioning of this biosensor, the roles of HMDA and GA percentages appear to be opposed when the extension of the linear response range is considered. Indeed, an increase of one unit in HMDA percentage (from 5 to 6 %) induces an increase in the extension of the linear response range equal to that obtained with a decrease of one unit of GA percentage (from 2.5 to 1.5%).     

Amperometric Glucose Biosensor Based on Rhodium Dioxide‐Modified Carbon Ink

An amperometric method for the determination of glucose using a screen printed carbon electrode is reported. The electrode material was bulk modified with rhodium dioxide and the enzyme glucose oxidase immobilized in a Nafion‐film on the electrode surface and investigated for its ability to serve as a detector of glucose in flow injection analysis. The sensor exhibited a linear increase of the amperometric signal with the concentration of glucose in the range of 1–250 mg L^?1 with a detection limit (evaluated as 3σ) of 0.2 mg L^?1 under optimized flow rate of 0.4 mL min^?1 in 0.1 M phosphate buffer (pH 7.5) carrier. At the potential applied (?0.2 V vs. Ag/AgCl), interferences from redox species present in the sample matrix were negligible. The biosensor reported here retained its activity for more than 40 injections or 4 months of storage at 6 °C. The RSD was determined as 1.8% for a glucose concentration of 25 mg L^?1 (n=5) with a typical response time of about 28 s.