锂/铌镁催化剂中碳酸锂的熔点与甲烷氧化偶联反应的活化和失活的关系

研究了铌掺杂的Li/MgO甲烷氧化偶联催化剂的反应性质及铌的助剂作用。铌的引入使得该催化剂上甲烷氧化偶联反应的活化温度降低50℃以上, 使此温度降到了催化剂中碳酸锂的熔点附近。试验观察到部分催化剂上甲烷氧化偶联反应的活性曲线在碳酸锂的熔点附近有一转折, 这一转折现象的出现与否及程度取决于制备条件。在碳酸锂的熔点附近, 含有铌的催化剂得到活化, 观察到无稀释气体时的反应引燃现象, 即温度增加几度活性便达到最大值。当在比碳酸锂熔点稍高的温度下且不稀释时反应, 含铌催化剂活性很高但很快失活, 在稍低于此熔点下则不失活, 但活性较低。这些试验结果表明, 含铌催化剂的活化与失活均与催化剂中的碳酸锂的相变化有关。试验还观察到了在稍高于碳酸锂的熔点下做寿命试验时, 甲烷氧化偶联反应的振荡现象。     

铁丝在氧气中燃烧的实验改进

“铁丝在氧气中燃烧”是初中化学教材中证明氧气化学性质的一个演示实验,该实验证明了氧气比较活泼,在一定条件下可以和金属发生剧烈反应。但是与木炭在氧气中燃烧、硫在氧气中燃烧、蜡烛在氧气中燃烧的演示实验相比,铁丝在氧气中燃烧的实验存在着一些不足的地方,针对这些不足,对铁丝在氧气中燃烧的实验进行了改进。1实验存在的问题按照教材要求,铁丝在氧气中燃烧的实验,须将铁丝绕成螺旋状,并在铁丝的末端绑上一根火柴杆,实验时先将火柴杆点燃,待火柴杆将燃尽时,迅速伸入盛满氧气的集气瓶中。这样的操作存在2个问题:第一,火柴燃烧的程度不…     

提高纤维素酶水解效率和降低水解成本

在我国可大量转化乙醇的是纤维质材料.纤维质材料转化乙醇的关键问题是纤维质转化为糖的过程,提高纤维素酶转化效率的方法有:(1)对纤维质材料进行预处理;(2)研究纤维素酶的最适作用条件;(3)纤维素酶的重复利用;(4)合理的发酵工艺等.本文分析了纤维素的结构以及纤维素酶的作用方式,总结了目前研究较多的几种纤维质材料预处理方法,及其对纤维素酶水解率的影响,并对研究纤维素酶的最适作用条件、纤维素酶的重复利用以及合理的发酵工艺进行了综述和分析.     

银镜的实验室制备

在高中化学“烃的衍生物”,“糖类、油脂、蛋白质”2章的教学中,安排了有关银镜反应的演示实验,其目的是通过实验证明含有醛基的有机物具有还原性。按照教材的方法进行实验操作,往往由于水浴的温度掌握不好,制得银镜的效果不理想。为了快速明显地观察到银镜的产生,采用平板玻璃     

2011年国际化学年《高分子通报》征稿启示

2011年是联合国确定的国际化学年,为纪念化学学科所取得的成就以及对人类文明的贡献,2011年化学年的主题是我们的生活,我们的未来。     

CO催化氧化用纳米材料及其最新研究成果

当前,环境问题和能源危机已经威胁到人类的健康和生存。用于环境治理和化学能源合成新概念的纳米催化材料越来越受到人们的关注。催化作为一个特殊的纳米现象,是纳米材料应用领域的一个重要方向,在环境净化、能量转化和新化学品的生产等方面具有广泛的应用前景。早期的一氧化碳(CO)催化氧化研究主要集中在催化剂的制备方法以及制备条件对催化反应的影响等方面。本文针对CO催化氧化这一基础课题,以影响CO催化氧化的关键因素(如金属颗粒的大小,金属与载体之间的相互作用以及载体本身的作用等)为主线,简要概述了近年来CO催化氧化的催化机理及相关催化剂的最新研究进展。同时,结合我们课题组的一些最新研究结果,进一步指出了纳米材料在CO催化氧化方面还存在的一些值得关注的问题,并对未来CO氧化催化剂的研究做出展望,提出一些可行的研究方向。     

漫话饮用水消毒剂

饮用水消毒剂的种类很多,国内大规模工业化生产主要还是用氯气来消毒。饮用水消毒的目的是杀灭水中可能引起霍乱、伤寒、痢疾等疾病的病菌与病毒。随着科学技术的发展和人们生活水平的提高,饮用水消毒剂也在不断发展,安全、高效、经济的消毒剂将成为主流。下面就目前使用或已开     

序言——《高分子通报》创刊20周年回顾

《高分子通报》是1988年10月创刊的。回顾20年来的发展历程,《高分子通报》是在各级领导的关怀下不断成长的,是在我国高分子科学领域的专家、学者的大力支持下发展的,也是在历届编委、编辑艰苦奋斗,辛勤耕耘下不断提高和前进的。早在1981年冬,昆明功能高分子学术会议中就正式提     

羟基甘氨酸溶液性质研究

采用核磁共振等仪器分析与官能团鉴定相配合的方法，对乙醛酸与铵盐反应形 成的羟基甘氨酸进行了研究。确认了羟基甘氨酸的结构，探讨了羟基甘氨酸的水溶 液中的主要存在形式，得出了与普遍接受的羟基甘氨酸在水溶液中不稳定的观点相 悖的结论。并对羟基甘氨酸的溶液稳定性，氨解，水解进行了研究。本结果为乙醛 酸以及羟基甘氨酸在有机合成上的应用提供了依据。     

在血卟啉衍生物光敏体系中DMPO捕集自由基的ESR研究

光照血卟啉衍生物(HPD)用于肿瘤的诊断和治疗已取得很大的成效,对此药理过程的分子机理的探索也开始引起生物和化学工作者的重视.我们的实验表明,在HPD光敏体系中自由基起着重要作用,特别是羟基自由基可能是HPD光致杀伤肿瘤细胞的主要原因.HPD光敏过程所产生的自由基的寿命极短,用化学方法或用一般ESR直接检测非常困难,但可被     

Chitin- and Streptavidin-Mediated Affinity Purification Systems: A Screening Platform for Enzyme Discovery

Affinity purification of recombinant proteins is an essential technique in biotechnology. However, current affinity purification methods are very cost-intensive, and this imposes limits on versatile use of affinity purification for obtaining purified proteins for a variety of applications. To overcome this problem, we developed a new affinity purification system which we call CSAP (chitin- and streptavidin-mediated affinity purification) for low-cost purification of Strep-tag II fusion proteins. The CSAP system is designed to utilize commercially available chitin powder as a chromatography matrix, thereby significantly improving the cost-efficiency of protein affinity purification. We investigated the CSAP system for protein screening in 96-well format as a demonstration. Through the screening of 96 types of purified hemoproteins, several proteins capable of the catalytic diastereodivergent synthesis of cyclopropanes were identified as candidates for an abiotic carbene transfer reaction.     

Affinity chromatography matures as bioinformatic and combinatorial tools develop

Affinity chromatography has the reputation of a more expensive and less robust than other types of liquid chromatography. Furthermore, the technique is considered to stand a modest chance of large-scale purification of proteinaceous pharmaceuticals. This perception is changing because of the pressure for quality protein therapeutics, and the realization that higher returns can be expected when ensuring fewer purification steps and increased product recovery. These developments necessitated a rethinking of the protein purification processes and restored the interest for affinity chromatography. This liquid chromatography technique is designed to offer high specificity, being able to safely guide protein manufactures to successfully cope with the aforementioned challenges. Affinity ligands are distinguished into synthetic and biological. These can be generated by rational design or selected from ligand libraries. Synthetic ligands are generated by three methods. The rational method features the functional approach and the structural template approach. The combinatorial method relies on the selection of ligands from a library of synthetic ligands synthesized randomly. The combined method employs both methods, that is, the ligand is selected from an intentionally biased library based on a rationally designed ligand. Biological ligands are selected by employing high-throughput biological techniques, e.g. phage- and ribosome-display for peptide and microprotein ligands, in addition to SELEX for oligonucleotide ligands. Synthetic mimodyes and chimaeric dye-ligands are usually designed by rational approaches and comprise a chloro-triazinlyl scaffold. The latter substituted with various amino acids, carbocyclic, and heterocyclic groups, generates libraries from which synthetic ligands can be selected. A 'lead' compound may help to generating a 'focused' or 'biased' library. This can be designed by various approaches, e.g.: (i) using a natural ligand-protein complex as a template; (ii) applying the principle of complementarity to exposed residues of the protein structure; and (iii) mimicking directly a natural biological recognition interaction. Affinity ligands, based on the peptide structure, can be peptides, peptide-mimetic derivatives (<30 monomers) and microproteins (e.g. 25-200 monomers). Microprotein ligands are selected from biological libraries constructed of variegated protein domains, e.g. minibody, Kunitz, tendamist, cellulose-binding domain, scFv, Cytb562, zinc-finger, SpA-analogue (Z-domain).     

抗体纯化中亲和色谱配体的研究进展

亲和色谱是用于抗体纯化的有效方法,本文对亲和色谱配体的研究进展进行了综述.     

亲和色谱中配基的筛选与应用

亲和配基的选择与筛选是发展新的亲和色谱填料或构建一个新的亲和色谱体系所必须解决的首要问题。该文结合作者所在实验室的工作,对配基的选择、筛选与应用方面的一些进展进行了简要评述。作者所在实验室针对特定蛋白质和多肽的多肽亲和配基的筛选,开展了反义肽简并性的研究,发展了基于反义肽的组合化学筛选新方法。与常规的组合合成法相比,该方法简单、快捷、有效,极大地减小了合成和筛选的工作量,降低了筛选后亲和组分结构鉴定的难度。所建立的筛选策略已应用于流感病毒、严重急性呼吸道综合征(SARS)病毒亲和抑制剂的筛选和用于人β-干扰素测定的石英晶体微天平（QCM）生物传感器的构建,均取得了有意义的结果。     

Displacement Chromatography of Proteins using Low Molecular Weight Anionic Displacers

A major impediment to the implementation of displacement chromatography has been the lack of suitable displacer compounds. Recently, it has been shown that low molecular weight dendritic polymers, protected amino acids and antibiotics can be successfully employed for displacement purification in cation-exchange systems. In this paper, a variety of low molecular weight anionic displacers are identified for the resolution of a bovine -lactoglobulin mixture into two closely related forms (A and B). A Dynamic Affinity plot is employed to evaluate the affinity of these low molecular weight compounds under various displacement conditions. In contrast to large polyelectrolyte displacers, the efficacy of these low molecular weight displacers are shown to be dependent on displacer concentration. In fact, the Dynamic Affinity Plot qualitatively predicts the transition from a displacement to a desorption regime with these low molecular weight displacers. In addition to the fundamental interest generated by low molecular weight displacers, it is likely that these displacers will have significant operational advantages as compared to large polyelectrolyte displacers. Furthermore, the ability to carry out selective displacement chromatography with these low molecular weight displacers offers significant potential for developing robust large scale displacement processes.     

Development and application of high‐performance affinity beads: Toward chemical biology and drug discovery

In drug development research, the elucidation and understanding of the interactions between physiologically active substances and proteins that numerous genes produce is important. Currently, most commercially available drugs and physiologically active substances have been brought to market without knowledge of factors interacting with the drugs and the substances. Affinity purification is a useful and powerful technique employed to understand factors that are targeted by drugs and physiologically active substances. However, use of conventional matrices for affinity chromatography often causes a decrease in efficiency of affinity purification and, as a result, more practical matrices for affinity purification have been developed for application in drug discovery research. In this paper, we describe the development of high‐performance affinity beads (SG beads and FG beads) that enable one‐step affinity purification of drug targets and the elucidation of the mechanism of the action of the drugs. We also describe a chemical screening system using our affinity beads. We hope that utilization of the affinity beads will contribute to the progress of research in chemical biology. © 2009 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 9: 66–85; 2009: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20170     

Toroidal Coil Countercurrent Chromatography in the Affinity Partitioning of Nicotinic Cholinergic Receptor Enriched Membranes

Abstract

A variation on the aqueous polymer phase partition method, affinity partitioning, has proved suitable for the preparative scale purification of binding site enriched membrane fragments. The full resolving potential of the affinity partitioning technique often requires the utilization of multiple extraction procedures such as countercurrent distribution. In this report, we evaluate the combination of a newly developed countercurrent purification technique, toroidal coil chromatography, with affinity partitioning. This approach provides an efficient method for purification and characterization of membrane bound nicotinic cholinergic receptors. The relative merits of the toroidal coil chromatography technology and the more conventional thin-layer countercurrent distribution techniques are compared.     

Reinigung der D-Oxynitrilase aus Mandeln mit Hilfe der Affinitäts-Chromatographie

A Rapid Purification of D -Oxynitrilase from Almond Meal by Affinity Chromatography Oxynitrilase from almond meal is capable of catalyzing the stereospecific addition of cyanide to a variety of aldehydes. Thus, the enzyme is potentially useful in the synthesis of optically active cyanohydrins on a preparative scale [1]. As the currently available purification procedures for this enzyme [2] are rather tedious, we have elaborated a simple and rapid procedure based on affinity chromatography. An inhibitor for the enzyme, methyl p-(3-aminopropoxy)benzoate (4) , has been synthesized and attached covalently to Sepharose 4B as a solid matrix (5) . With this affinity gel it was possible to prepare the D -oxynitrilase in a simple procedure with high yields.     

亲和膜色谱技术研究进展

对一种崭新的生物大分子分离技术－－亲和膜色谱技术做了全面的评述,介绍了亲和膜色谱分离的过程,评价了亲和膜基质材料活化、改性方法、给出了配基间隔臂的选择原则,概括了亲和膜色谱理论研究的进展,并对亲和膜色谱技术进行了展望。     

Polymeric supports for affinity chromatography and high-performance affinity chromatography

Affinity chromatography is the most selective chromatographic method for the purification of biologically active materials. It is based on the biospecific interaction of the substrates with a ligand, which is chemically immobilized onto a suitable matrix (support). Different matrices provided by natural and synthetic polymers are used for the preparation of affinity supports. In this communication we describe and compare the properties of various supports based on polysaccharides, polyacrylamides and inorganic materials. In particular, we discuss the utility of different silica derivatives (especially primary hydroxyl silica) for the immobilization of ligands and high-performance affinity chromatography.