GOx@GA@MIL-101金属有机骨架用于葡萄糖的快速比色识别

金属有机骨架(MOFs)材料具有均匀的孔隙率和大的比表面积,可作为固定化酶的载体。然而,固定化酶由于较长响应时间或酶易泄漏的缺点阻碍了其应用。本研究选取类过氧化物酶 MIL-101为载体,戊二醛(GA)为交联剂,通过交联法将葡萄糖氧化酶(GOx)固定在载体上,建立了模拟多酶体系GOx@GA@MIL-101。制备的复合物可进一步高效催化级联反应检测葡萄糖。GOx@GA@MIL-101具有更快的催化变色效果(30 s)。     

纳米载体固定化酶的最新研究进展

催化剂是化学工业的重要基础,其中酶是重要的高效天然催化剂。近年来,酶被越来越多地应用于工业领域,如精细化工、食品工业、制药工业、纺织业和制浆造纸。然而,由于游离酶存在价格昂贵及操作稳定性(特别是回收与重复使用性能)低等缺点,其在工业上的进一步应用受到一定限制。对酶进行固定化是解决上述问题的有效途径。一个理想的酶固定化技术需要载体具有良好的生物相容性和高比表面积,能够负载适量的酶并且具有很好的重复使用性能,固定化酶的过程简单温和,所得到的固定化酶制剂具有良好的催化性能、稳定性以及工业应用价值。尽管固定化酶技术经过了多年的发展,但仍需进一步研究。近几年,人们研究了基于纤维素纳米晶类、聚多巴胺类纳米载体以及生物相容性合成有机物纳米胶等新型载体对酶的固定化,取得了较好的成果。本文综述了这些新型纳米载体的制备以及酶的固定化过程,阐述了纳米载体固定化酶的结构和催化性能,并展望了发展前景。纤维素是全球产量最高、来源最广的生物聚合物。纤维素经过一定的酸(常用硫酸和盐酸)水解处理后,剩下的是具有高结晶度的纤维素纳米晶。它具有高比表面积、高机械强度和高长径比等优异性能。因此,研究者利用纤维素纳米晶作为载体进行酶固定化,获得了高负载量、高催化性能的固定化酶制剂。基于仿生矿化法制备的聚多巴胺类材料近年来获得研究者越来越多的关注。多巴胺具有良好的自聚合能力,可以对无机、有机等各种材料进行表面修饰。同时,聚多巴胺中含有的活性官能团可以与酶发生交联,从而达到固定化酶的效果。基于合成性聚合物纳米胶载体的固定化酶技术同样是一个新兴的、有意义的研究领域。相关的固定化过程可分为两大类：(1)在酶分子表面通过原位聚合生成纳米胶(growing-from过程);(2)将酶与预先合成的纳米胶进行交联(grafting-to过程)。其中, growing-from过程是先将酶分子丙烯酰化,再进行原位聚合。而原位聚合又可分为自由基聚合、原子转移自由基聚合(ATRP)和可逆加成-断裂链转移聚合(RAFT)。其中, ATRP和 RAFT主要用于制备环境响应型的酶-聚合物纳米凝胶。     

核苷酸锆固定化脂肪酶的制备及其催化性能

开发了以核苷酸锆纳米颗粒为载体固定化脂肪酶的方法,考察了固定化时间、缓冲液pH值及浓度和酶载量等因素对固定化酶在有机相中催化烯丙醇酮酯交换反应性能的影响.结果表明,一元尿苷酸锆(粒径30～50nm)是较佳的载体,在磷酸缓冲液pH=8.0和浓度为0.03mol/L时,酶与载体质量比为4,固定化6h制得的固定化酶效果最佳....     

纳米载体固定化酶的最新研究进展（英文）

催化剂是化学工业的重要基础,其中酶是重要的高效天然催化剂.近年来,酶被越来越多地应用于工业领域,如精细化工、食品工业、制药工业、纺织业和制浆造纸.然而,由于游离酶存在价格昂贵及操作稳定性(特别是回收与重复使用性能)低等缺点,其在工业上的进一步应用受到一定限制.对酶进行固定化是解决上述问题的有效途径.一个理想的酶固定化技术需要载体具有良好的生物相容性和高比表面积,能够负载适量的酶并且具有很好的重复使用性能,固定化酶的过程简单温和,所得到的固定化酶制剂具有良好的催化性能、稳定性以及工业应用价值.尽管固定化酶技术经过了多年的发展,但仍需进一步研究.近几年,人们研究了基于纤维素纳米晶类、聚多巴胺类纳米载体以及生物相容性合成有机物纳米胶等新型载体对酶的固定化,取得了较好的成果.本文综述了这些新型纳米载体的制备以及酶的固定化过程,阐述了纳米载体固定化酶的结构和催化性能,并展望了发展前景.纤维素是全球产量最高、来源最广的生物聚合物.纤维素经过一定的酸(常用硫酸和盐酸)水解处理后,剩下的是具有高结晶度的纤维素纳米晶.它具有高比表面积、高机械强度和高长径比等优异性能.因此,研究者利用纤维素纳米晶作为载体进行酶固定化,获得了高负载量、高催化性能的固定化酶制剂.基于仿生矿化法制备的聚多巴胺类材料近年来获得研究者越来越多的关注.多巴胺具有良好的自聚合能力,可以对无机、有机等各种材料进行表面修饰.同时,聚多巴胺中含有的活性官能团可以与酶发生交联,从而达到固定化酶的效果.基于合成性聚合物纳米胶载体的固定化酶技术同样是一个新兴的、有意义的研究领域.相关的固定化过程可分为两大类:(1)在酶分子表面通过原位聚合生成纳米胶(growing-from过程);(2)将酶与预先合成的纳米胶进行交联(grafting-to过程).其中,growing-from过程是先将酶分子丙烯酰化,再进行原位聚合.而原位聚合又可分为自由基聚合、原子转移自由基聚合(ATRP)和可逆加成-断裂链转移聚合(RAFT).其中,ATRP和RAFT主要用于制备环境响应型的酶-聚合物纳米凝胶.     

石墨烯固定化酶研究进展

固定化酶具有高效催化、可重复利用及易分离等优点,在食品、医药等工业生产领域及微观生化检测领域具有广泛应用。固定化酶的性能与载体材料关系密切。石墨烯作为一种广受关注的纳米材料,其独特而优良的物化性能是固定酶的理想载体。本文主要介绍了近年来以石墨烯及其衍生物为载体的固定化酶技术的发展状况。重点对以物理吸附法、化学键合法和包埋法为主的各种石墨烯固定化酶的制作方法,以及其在酶微反应器和生物传感等领域的最新应用进行详细的评述,并对其今后的发展前景进行了展望。     

固定化酶微反应器的制备及应用

固定化酶微反应器是将生物分子固定技术与生化微反应相结合制备的一种固定化催化装置。这种微型化的反应系统由于兼具固定化酶的特异性催化、可重复利用及微分析的低消耗、易分离等优点,在生命科学如蛋白质组学、酶抑制剂的筛选、生物催化等领域具有非常重要的作用。固定化酶微反应器的性能与其制作方法关系密切。本文着重从酶与固定化载体结合方式的角度,对近年来固定化酶微反应器的各种制备方法和应用进行了较为详细的评述。重点讨论了各种方法的优缺点和最新的发展情况,并对其发展前景进行了展望。     

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.     

固定化脂肪酶催化麻疯树油与碳酸二甲酯制备生物柴油的研究

以介孔硅材料(MPS)为载体将脂肪酶固定化,以碳酸二甲酯为酰基受体,对固定化酶催化碳酸二甲酯进行了反应路径(原料油)、反应条件(反应温度、碳酸二甲酯的用量、加水量)的优化,在最佳的条件下对实验过程中所用的固定化酶进行重复使用性的考察。实验结果表明,不同种油与碳酸二甲酯反应在固定化酶的催化下制备生物柴油的产率以麻疯树油为最高,最佳反应条件是碳酸二甲酯的浓度为16m L/g、不加水,在50℃下反应24h,生物柴油得率达81.6%。     

固定化L-天门冬酰胺酶活性的X射线微区分析

1　引　　言固定化L 天门冬酰胺酶的研究长期以来倍受人们的关注。共价法是一种常用的方法 ,该方法通过载体与酶之间形成共价键而将酶固定于载体上 ,这样可防止酶的脱落 ,故而起到了催化作用。对固定化L 天门冬酰胺酶进行活性定位的研究 ,将有助于L 天门冬酰胺酶的固定化 ,其活性定位的基本原理如下 :底物 酶 产物 +捕捉剂 (金属离子 )活性部位沉淀利用聚焦电子束对固定化酶表面进行激发 ,有活性的部位发射出沉淀金属的特征X 射线 ,利用X 射线能谱分析即可定位酶的活性部位。本文利用MgCl2 作为捕捉剂 ,以L 天门冬酰胺为底物 ,经固定化L…     

新型疏水性酶载体的合成及其性能研究

研究了聚丙烯酸酯类疏水性固定化酶载体(包括环氧基和胺基)的合成,旨在提高载体固载酶的性能。结果表明,所得载体的孔结构适合固定化青霉素酰化酶、D-氨基酸氧化酶、DL-7-ACA酰化酶、头孢菌素C酰化酶等。固定化D-氨基酸氧化酶的酶活与载体的含水量(与其孔结构相关)有密切的关系;载体的突出优点是固载酶时,酶的固定化效率可高达50%。     

Immobilization of glucose isomerase and its application in continuous production of high fructose syrup

Bilayer glucose isomerase was immobilized in porousp-trimethylaminepolystyrene (TMPS) beads through a molecular deposition technique. Some of the factors that influence the activity of immobilized glucose isomerase were optimized, with the enzyme concentration of 308 IU/mL, enzyme-to-matrix ratio of 924 IU/g wet carrier, and hexamethylene bis(trimethylammonium iodine) concentration of 15 mg/mL giving the maximum catalytic activity (2238 IU/g dry gel) of the immobilized bilayer glucose isomerase, retaining 68.5% of the initially added activity. The half-life of the immobilized bilayer glucose isomerase was approx 45 d at pH 8.5, 60°C, with 50% (w/v) glucose as substrate. The specific productivity of the immobilized bilayer glucose isomerase was 223 g dry D-glucose/g dry immobilized enzyme per d.     

Immobilization of glucose isomerase and its application in continuous production of high fructose syrup

Bilayer glucose isomerase was immobilized in porousp-trimethylamine-polystyrene (TMPS) beads, through a molecular deposition technique. Some of the factors that influence the activity of immobilized glucose isomerase were optimized, with the enzyme concentration of 308 IU/mL, enzyme:matrix ratio of 924 IU/g wet carrier, and hexamethylenebis(trimethylammonium iodine) concentration of 15 mg/mL, giving the maximum catalytic activity (2238 IU/g dry gel) of the immobilized bilayer glucose isomerase, retaining 68.5% of the initially added activity. The half-life of the immobilized bilayer glucose isomerase was approx 45 d at pH 8.5, 60°C, with 50% (w/v) glucose as substrate. The specific productivity of the immobilized bilayer glucose isomerase was 223 g dry D-glucose/g dry immobilized enzyme per day.     

Preparation of an ultrafiltration membrane from the copolymer of acrylonitrile–glycidylmethacrylate utilized for immobilization of glucose oxidase

Ultrafiltration membrane has been prepared from the copolymer of acrylonitrile–glycidylmethacrylate and the porosity of the membrane was studied. The asymmetric structure was proved by scanning electron microscopy. The basic characteristics of the membrane were measured – water permeability, water content, membrane selectivity, etc. The membrane obtained was used as a carrier for immobilization of glucose oxidase. The immobilization was carried out covalently by two methods: direct bonding of the enzyme and indirectly by a spacer (hexamethylenediamine) and cross-linking agent (glutar aldehyde). The amount of bound protein and relative activity of the immobilized glucose oxidase were determined. Temperature optimum, pH optimum and storage stability of the immobilized glucose oxidase were determined. It was proved that glucose oxidase immobilized by the direct method shows better characteristics compared with the indirect method.     

Conductometric Flow-Injection Glucose Biosensing System with an Immobilized Glucose-Oxidase Mini-Reactor

A flow-injection conductometric manifold equipped with an immobilized glucose-oxidase mini-reactor was proposed for the determination of glucose concentration. The glucose of the injected sample plug was oxidized enzymatically to its δ-lactone, and the hydrolysis of the lactone generated a concentration-dependent flow-injection signal. The dynamic range was from the tens of μM to the mM order of glucose; the immobilized enzyme reactor was stable for at least several months. The pH of the carrier solution was maintained in a slightly alkaline region (ca. 8.0 by 500 μM of Tris-HCl) to accelerate the spontaneous hydrolysis of δ-gluconolactone. The repeatability of the flow-injection signals was improved (CV < 3%, n = 7) by the addition of Triton X-100® (0.7% w/v) into the carrier solution.     

High-performance cascade nanoreactor based on halloysite nanotubes-integrated enzyme-nanozyme microsystem

Various enzymatic reactions or enzymatic cascade reactions occur efficiently in biological microsystems due to space constraints or orderly transfer of intermediate products. Inspired by this, the horseradish peroxidase(HRP)-like nanozyme(Fe-aminoclay) was in situ synthesized on the surface of alkali-activated halloysite nanotubes and the natural enzyme(glucose oxidase, GOx) was immobilized on it to construct a high-efficiency GOx-Fe AC@AHNTs cascade nanoreactor. In which, Fe AC@AHNTs can not on...     

IMMOBILIZATION OF GLUCOSE OXIDASE AND CELLULASE BY CHITOSAN— POLYACRYLIC ACID COMPLEX

This study is concerned with chitosan-polyacrylic acid complex as a carrier to immobilize glucose oxidase (GOD)and cellulase. The optimum emperature of the immobilized GOD (IG) was determined to be 60℃which is higher than that of the native GOD about 40℃. The optimum temperature of the immobilized cellulase (IC) was determined to be about 30℃higher than that of native cellulase. Both of the optimum pH of IG and IC shifted one pH unit to acid. Immobilized enzyme may be used in more wide pH range. Their storage life are much longer compared with their native states. Both of them can be reused at least 12 times.     

Immobilization of growing cells by polyethyleneimine-modified alginate

A unique polymer matrix that is suitable for immobilizing growing cells has been developed. Alginate was chemically modified with polyethyleneimine (PEI), and the resultant polymer aggregate was evaluated as a cell carrier. Our method of immobilization depends on reversible gelation of the PEI-modified alginate. Our hypothesis is that immobilized cells grow by dissolving the surrounding gel matrix; the dissolved polymer adduct is displaced peripherally and gelled again by the influx of calcium ion from the surrounding fermentation broth, retaining both cells and carrier polymer in the gel beads. Thus, the immobilized cells gain space for growth by expanding the carrier matrix. The PEI modification offers the following advantages: (1) improved mechanical strength; (2) improved cell retention; (3) increased catalyst life; (4) ease of pelletization; and (5) an apparent bacteriostatic capability. When immobilized yeast cells were applied to a continuous ethanol fermentation, 94% theoretical conversion of glucose to ethanol was observed, with a reactor productivity of 15–30 g/L/h in a nonsterile reactor. A 3-mo catalyst life and minimal cell washout were observed.     

STUDIES ON IMMOBILIZED GLUCOSE OXIDASE BY DIETHYLAMINOETHYL CELLULOSE COMPLEXES

The properties of immobilized glucose oxidase (GOD) by the complexes of diethylaminoethyl cellulose(DEAEC) with different polymers, such as polymethylacrylic acid (PMAA), polyacrylic acid (PAA), polystyrene sulfonic acid (PSSA), polyvinylaleohol (PVA), polyethylene oxide (PEO) and styrene-maleic acid copolymer (PSMA) were investigated. The activity of immobilized GOD was obviously influenced by the component of the DEAEC complexes. The relative activity of the immobilized GOD reached to maximum and over 90% of the native GOD. when the DEAEC-PMAA DEAEC-PAA complexes were used as a carrier with the molar ratio of DEAEC and polyacid of about one. Michaelis constants (Km) of the immobilized enzymes of DEAEC-GOD-PMAA and DEAEC-GOD-PAA were determined to be 1.25 and 1.00, respectively. Moreover, the immobilized GOD has a good storage stability and cyclic life.     

A Fiber Optic Biosensor Based on Hydrogel-Immobilized Enzyme Complex for Continuous Determination of Cholesterol and Glucose

A multiparameter fiber optic biosensor for continuous determination of cholesterol and glucose was developed. This sensor was based on poly(N-isopropylacrylamide) (PNIPAAm)-immobilized glucose oxidase (GOx) complex (PIGC) and immobilized cholesterol oxidase (COD). The immobilized COD catalysis to the oxidation of cholesterol and PIGC catalysis to the oxidation of glucose could be performed at different temperatures. Therefore, the sensor could detect cholesterol and glucose continuously by changing temperature. The optimal detection conditions for glucose were achieved with pH 6.5, 30 °C, and 10 mg GOx (in 100-mg carrier), and those for cholesterol were achieved with pH 7.5, 33 °C, and 25 mg COD (in 250-mg carrier). The sensor has the cholesterol detection range of 20–250 mg/dL and the glucose detection range of 50–700 mg/dL. This biosensor has outstanding repeatability and selectivity, and the detection results of the practical samples are satisfactory.