超声波对固定化辣根过氧化物酶活性影响研究

为了研究超声波对固定化酶活性的影响,以固定化辣根过氧化物酶为对象,研究了不同超声波处理条件(超声功率,超声时间)以及超声条件下催化体系的pH、温度对固定化酶活性的作用。同时对超声波处理后固定化酶活的重复利用性进行测定。结果表明,超声波处理对提高固定化酶在高温、强酸碱条件下催化活性有一定帮助,最佳处理条件为:超声波功率50 W,超声时间30 min,pH 8,温度35℃,在此条件下,与未经超声波处理相比,固定化酶活性提高了17.6%,固定化酶重复利用性增强,经7次使用后,固定化酶催化活性是未经处理的1.8倍。     

辣根过氧化物酶活性中心的模拟及其分析应用的研究

合成了锰(IH)与 meso-四(4-三甲铵基苯)卟啉的螯合物(Mn-T(4-TMAP)P),研究了Mn-T(4-TMAP)P 作为过氧化物模拟酶对过氧化氢、安替比林和苯酚显色反应的催化活性。拟订的分光光度法测定0～6μg/ml H_2O_2,5μg 和10μg H_2O_2的平均回收率为97.6%和99.4%,变异系数为2.2%和1.1%。与葡萄糖氧化酶催化反应偶联,可用于人血清中葡萄糖含量的测定,结果满意。     

过氧化物酶应用的生物技术进展

介绍了过氧化物酶可以催化的四种反应类型 :氧化去氢反应、氧化卤化反应、双氧水歧化反应、氧传递反应。综述了过氧化物酶在有机合成等反应中的应用前景。认为氯过氧化物酶是一种应用最广的过氧化物酶 ,在催化有机反应时 ,具有更高的手性选择性和酶稳定性     

铁掺杂蒙脱石纳米酶的制备与应用EI北大核心CSCD

纳米酶可以快速灵敏地检测生物标记物,有效防止疾病的爆发,但是纳米酶的催化活性低、对底物亲和力差,严重地制约了其检测性能。蒙脱石是一种具有典型的2:1型层状结构的硅酸盐黏土矿物,利用其良好的吸附能力和阳离子交换能力,将Fe^(3+)锚定在蒙脱石的表面与层间,制备具有类过氧化物酶性质的Fe掺杂蒙脱石纳米酶,可增强对H_(2)O_(2)的亲和力,通过比色法可实现对H_(2)O_(2)的检测。结果表明:在中性条件下,H_(2)O_(2)的检测线性范围和检测限分别为20~500μmol/L和5.8μmol/L。这种蒙脱石纳米酶在分析检测和疾病诊断领域具有良好的应用前景。     

辣根过氧化物酶处理邻苯二酚废水的研究

研究了用辣根过氧化物酶催化处理邻苯二酚废水的效果.结果表明,用辣根过氧化物酶可以有效地去除邻苯二酚.其最佳处理条件为:pH值4.4、过氧化氢与邻苯二酚的摩尔比约2∶1、反应时间30 min,适当增加酶用量可以明显缩短反应时间.     

过氧化物酶的应用研究进展

过氧化物酶在过氧化物氧化底物的过程中起着重要的作用,广泛应用于生物技术领域.过氧化物酶的热不稳定性是抑制其应用的主要因素,现正设计成新的催化剂形式来克服其稳定性问题,增加其热稳定系数.     

对氨基联苯-H2O2-HRP分光光度法测定HRP的研究

提出了对氨基联苯-H2O2-辣根过氧化物酶(HRP)催化动力学光度法测定HRP的新方法.在辣根过氧化物酶的催化作用下,H2O2氧化对氨基联苯生成有色的偶氮联苯化合物,通过分光光度计在波长455nm处测其吸光度值,可间接测定HRP的含量.在所选定的实验条件下,测定HRP的线性范围为3.0×10-10～8.0×10-8g/mL,检测限为3.0×10-10g/mL.     

基于金属硫蛋白铜纳米簇的过氧化物酶活性检测尿酸

将金属硫蛋白铜纳米簇的过氧化物酶活性与尿酸酶的催化活性相结合,设计了比色/光度法检测血液样品中尿酸的生物传感平台。方法检测尿酸的线性范围为25.47～750.00μmol/L,检出限7.72μmol/L,相对标准偏差为3.02%～4.62%,在实际血液样品的测定中加标回收率96.34%～105.39%。方法简便易行,能满足实际应用需要。     

基于金属硫蛋白铜纳米簇的过氧化物酶活性检测尿酸

将金属硫蛋白铜纳米簇的过氧化物酶活性与尿酸酶的催化活性相结合,设计了比色/光度法检测血液样品中尿酸的生物传感平台。方法检测尿酸的线性范围为25.47～750.00μmol/L,检出限7.72μmol/L,相对标准偏差为3.02%～4.62%,在实际血液样品的测定中加标回收率96.34%～105.39%。方法简便易行,能满足实际应用需要。     

不同培养条件对云芝(Coriolus versicolor)木质素降解酶产酶影响的研究

本文研究了不同培养条件对云芝（Coriolusversicolor）三种木质素降解前产酶的影响，发现三种木质素降解酶即水质素过氧化物酶（Lip）、赖锰标木质素过氧化物酶，（Mnp）和漆酶的产生和培养条件关系很大，添加黎芦醇（VOH）能显著地提高三种酶的产量，当VOH浓度为1mmol／L时，可使木质素过氧化物酶产量提高10倍，添加Mn2＋对赖锰木质素过氧化物酶有促进作用，但对木质素过氧化物酶有抑制作用。提高其它微量元素（Cu2+，Fe2+,Zn2+，Ca2+）等同样能显著促进三种酶的产生。采用30信浓度时，赖锰木质素过氧化物酶的量要比1培浓度时提高6倍。三种酶的最适产酶pH相差很大，木质素过氧化物酶在pH4．5～5．5左右，赖锰木质素过氧化物酶在PH5．5～6.5左右，而漆酶则抵达pH3．5～4．0．Tween80在低浓度时（0.01％-0.02％）有一定的促进作用，而在高浓度则有抑制作用。C／N比则是影响产酶的另一因素，低碳培养基比低氮培养基更适宜三种木质素降解酶的产生。同时，在低氮培养基和低碳培养基下，上述因素对三种酶产生的影响也存在显著差异。这有可能是云芝的木质素降解酶在不同的C／N下其产生机理存在差异。     

Artificial enzyme with magnetic properties and peroxidase activity on indoleamine metabolite tumor marker

Stable and easily-handled synthetic materials mimicking natural enzymes activity would find important biotechnological applications. This article describes the synthesis and characterization of magnetic molecularly imprinted catalytic polymers that exhibit peroxidase-like activity towards 5-hydroxyindole-3-acetic acid (5-HIAA) oxidation. This multifunctional material is obtained from highly crystalline magnetite nuclei coated with a silica layer to protect the iron nucleus from oxidation and to provide anchoring for hydroxyl surface groups. After acrylic functionalization via sol–gel process, a molecularly imprinted polymer with hemin as catalytic center and 5-HIAA as template has been successfully attached to the structure. The resulting hybrid composite is magnetically separable and possesses excellent catalytic ability for the selective oxidation of the indoleamine metabolite tumor marker, showing Michaelis–Menten kinetics with this molecule but not towards other structural analogs. Therefore, it can be considered an artificial peroxidase enzyme.     

The synthesis and catalytic activity to Li/SOCl2 battery of two new porphyrins

Two new porphyrins (3a, 3b) were synthesized and characterized by IR, UV–vis, ¹H NMR, MS and elementary analysis. The catalytic activity of the synthesized porphyrins to lithium/thionyl chloride (Li/SOCl₂) battery is evaluated by the relative energy of the battery whose electrolyte contains the porphyrins. The results indicate that the energy of Li/SOCl₂ battery catalyzed by porphyrins 3a and 3b is 101, 37% higher, respectively, than that of Li/SOCl₂ battery in the absence of the porphyrins. It can be used as a basis for the synthesis of more porphyrins with improved catalytic activity to Li/SOCl₂ battery in the future.     

Oxidation of polycyclic aromatic hydrocarbons with hydrogen peroxide catalyzed by Iron(III)porphyrins

A variety of iron-metallated functional porphyrins have been synthesized and their catalytic activity to oxidize polycyclic aromatic hydrocarbons, (PAHs) using hydrogen peroxide as oxidant was investigated. It was found that iron-metallated porphyrins bearing strong electronegative groups at β-pyrrolic positions show an exceptionally high catalytic efficiency.     

Towards NO-free Regulation of sGC: Design and Synthesis of trans-AB-porphyrins

The pathogenesis of the cardiovascular system is often associated with dysfunction of soluble guanylate cyclase (sGC), which can be stimulated in both an NO-dependent and -independent manner. It was previously reported that PPIX and its amphiphilic derivatives markedly activate the enzyme. To date, all porphyrins studied are naturally occurring compounds or their derivatives, possessing substituents at β-positions. Such porphyrins are of limited abundance and their derivatives or analogues are difficult to synthesize, while synthetic meso-substituted porphyrins are easy to prepare. Thus, we have decided to study their effect on guanylate cyclase. To this end, a series of trans-AB-porphyrins, bearing both hydrophilic and hydrophobic groups at the opposite ends of the macrocycle, loosely mimicking the arrangement of the substituents in PPIX, was design and synthesized. Their synthesis involves preparation of suitable building blocks – dipyrromethanes, starting from aldehydes or acetals and following an acid-catalyzed [2+2]-dipyrromethane condensation. Biological properties of synthesized porphyrins with regard to sGC activation were tested. meso-Substituted porphyrins do interact with sGC, though they are poor activators, indicating that further optimization of their structure is required.     

Hydrogen peroxide sensors for cellular imaging based on horse radish peroxidase reconstituted on polymer-functionalized TiO₂ nanorods

We describe the reconstitution of apo-horse radish peroxidase (apo-HRP) onto TiO(2) nanorods functionalized with a multifunctional polymer. After functionalization, the horse radish peroxidase (HRP) functionalized TiO(2) nanorods were well dispersible in aqueous solution, catalytically active and biocompatible, and they could be used to quantify and image H(2)O(2) which is a harmful secondary product of cellular metabolism. The shape, size and structure of TiO(2) nanorods (anatase) were analyzed by transmission electron microscopy (TEM), high resolution TEM (HRTEM), electron diffraction (ED) and X-ray diffraction (XRD). The surface functionalization, HRP reconstitution and catalytic activity were confirmed by UV-Vis, FT-IR, CLSM and atomic force microscopy (AFM). Biocompatibility and cellular internalization of active HRP reconstituted TiO(2) nanorods were confirmed by a classical MTT cytotoxicity assay and confocal laser scanning microscopy (CLSM) imaging, respectively. The intracellular localization allowed H(2)O(2) detection, imaging and quantification in HeLa cells. The polymer functionalized hybrid system creates a complete sensor including a "cell positioning system" in each single particle. The flexible synthetic concept with functionalization by post-polymerization modification allows introduction of various dyes for sensitisation at different wavelengths and introduction of various anchor groups for anchoring on different particles.     

Metalloporphyrins encapsulated mesoporous molecular sieves as efficient heterogeneous catalysts for oxidation of cyclohexene with iodosylbenzene

The cationic Fe, Mn or VO porphyrins were encapsulated in Si, Al, Ti and V-MCM-41. The catalytic activity was investigated for the oxidation of cyclohexene with iodosylbenzene (PhIO) as oxidant. Manganese porphyrin supported catalysts produces epoxide as major products whereas iron and vanadyl porphyrins gave allylic oxidation products as major constituents. The results obtained clearly shows that the selectivity of various products depends not only on the nature of the support materials but also on the combined effects of metalloporphyrins and the supports. The recyclability of the heterogeneous catalysts was also investigated. The decrease in catalytic activity and leaching of active centers were observed when porphyrins were supported on Si-MCM-41.     

Superior Peroxidase-Like Activity of Gold Nanorattles in Ultrasensitive H2O2 Sensing and Antioxidant Screening

Nanozymes are artificial enzyme systems which are easy to produce, highly stable and cost-effective in comparison to natural enzymes. Herein, we evaluated the peroxidase-like activity of gold nanorattles (Au NRTs) having a solid gold octahedron core and thin, porous cubic gold shell. We also prepared solid gold nanocubes and nanospheres of similar sizes and surface charge as that of Au NRTs and compared their activity with standard horse radish peroxidase (HRP). All the prepared nanostructures followed Michaelis-Menten kinetics as observed from their substrate concentration vs. initial reaction velocity plot using 3,3’,5,5’-tetramethylbenzidine (TMB) as a substrate. The kinetic parameters and the catalytic efficiency for the peroxidase-like activity of the nanostructures and HRP were calculated, and it was observed that Au NRTs possess the best nanozymatic activity with lowest K_M and highest catalytic efficiency (k_cat/K_M). The better activity of Au NRTs compared with other nanostructures and HRP could be attributed to the hollow porous structure with a solid core where different surfaces are available for reaction. Au NRTs, being the best amongst the tested nanozymes were further used for the sensing of hydrogen peroxide (H₂O₂) and were found to sense H₂O₂ down to 0.5 μM. Further, two naturally occurring antioxidants, tannic acid and ascorbic acid showed inhibitory effect on the peroxidase-like activity of Au NRTs in a concentration dependent manner which can be further used for screening of antioxidants or for determining the antioxidant potential.     

Porphyrin polymers and organic frameworks

The versatility of porphyrins as optoelectronic or catalytic units makes them attractive elements for inclusion in functional materials. Polymers that include porphyrins have been created with a wide variety of structures and used in a wide range of applications. This review covers recent developments in the synthesis, characterization and applications of polymeric materials in which porphyrins are key components of the repeat units, including the rapidly growing area of metal–organic frameworks and related covalent organic frameworks. © 2015 Society of Chemical Industry     

Distribution of vanadyl porphyrins in a Mexican offshore heavy crude oil

The present work entails a study made regarding vanadyl porphyrins distribution of Mexican heavy crude oil from Sonda de Campeche offshore field (drilling range 4350–4371 m) in the southeast of Gulf of México. Furthermore, according to planning request about future trends of refining schemes the distribution of vanadyl porphyrins was investigated in the total heavy crude oil and their distilled residue, free of the asphaltene fraction. Vanadyl-metaloporphyrins were extracted and separated by means of adsorption chromatographic schemes using adsorbents and solvents of increasing polarities. Vanadyl porphyrins were identified and characterized by ultraviolet and visible (UV-vis) spectrophotometry, high-performance liquid chromatography (HPLC) and mass spectrometry (MS). Results show that vanadyl porphyrins are present in the total crude oil and within the deasphalted residue, namely five homologues series DPEP, ETIO, THBD, BD and B with the ETIO series predominating in deasphalted residue. On the whole, data related to the distribution of vanadyl porphyrins indicates the convenience of using procedures that eliminate asphaltenes in order to remove vanadyl porphyrins and improve the efficiency of catalysts used in different catalytic refining processes.     

取代铁卟啉催化氧化邻硝基甲苯绿色合成邻硝基苯甲酸

研究了一种在乙醇水溶液中,以取代铁卟啉为仿生催化剂,催化氧气氧化邻硝基甲苯绿色合成邻硝基苯甲酸的新方法。考察了不同取代铁卟啉催化剂对反应活性和主产物选择性的影响,发现所有铁卟啉均有活性,且卟啉环外取代基从强给电子基（—OH）到吸电子基（—NO₂）变化时,其催化活性（原料转化率）变化不大,但对主产物的选择性影响却很明显,其中T(p-Cl)PPFeCl的催化活性和选择性均为最好,含最强给电子基（—OH）或最强吸电子基（—NO₂）的金属卟啉对主产物的选择性均最低。考察了溶剂中乙醇的体积分数对反应的影响,发现在乙醇浓度为80 % 时,产物的选择性最高。系统地考察了碱浓度、氧气压力、温度、时间、原料初始浓度等因素对反应的影响,找到了优化的工艺条件。发现以T(p-Cl)PPFeCl为催化剂,当乙醇浓度为80%、碱浓度为3. 75 mol·L^-1时,在2. 0 MPa、55℃条件下反应12 h,邻硝基甲苯的转化率达到79. 7%,邻硝基苯甲酸的选择性和收率分别可达95. 8% 和76. 3%。