Theoretical Analysis on Magnetic Properties of Conjugated Organic Molecules Containing Borepin

Theoretical study about the magnetic properties of conjugated organic molecules containing borepin with π current density was carried out. 1-(2,4,6-Trimethylphenyl)borepin moiety is the center and other different groups are situated on the both β sides, which are named molecules 1-12 as theoretical model in order to establish the relationship between aromaticity and geometry variation of borepin. The optimized molecular structures of molecules 1-12 are almost keeping planar and the C2-C3 bond length of borepin turns longer from molecule 1 to molecule 12. Different borepin-annulated ring could change the conjugated effect of π-electron between borepin and these borepin-annulated rings. Moreover, the molecule presents antiaromaticity, in other words, the molecule became unstable when the C2-C3 bond length of borepin extended more than ca. 0.1417 nm. But the β position fragment and substituent groups of borepin are not affected in this case, they are still steady. However, the central borepin ring current is counteracted by symmetrical overlap of it with affiliated borepin-annulated ring current. Hence, the central borepin ring breaking would be liable to occur. These molecules have higher vertical ionization potentials(VIPs) and lower vertical electron affinities(VEAs), which suggests that these molecules could easily exist in anionic form.     

金钯二元小团簇的几何结构与电子性质

在UBP86/LANL2DZ和UB3LYP/def2-TZVP水平下详细研究了AumPdn(m+n≤6)团簇的几何结构和电子性质.阐明了团簇的结构特征、平均结合能、垂直电离势、垂直电子亲和能、电荷转移以及成键特征.除单取代混合团簇(AunPd和AuPdn,n=5或6)外,五和六原子混合团簇中钯原子趋于聚集到一起形成Pdcore,金原子分布在Pdcore周围形成PdcoreAushell结构.含一个和两个钯原子团簇的电子性质与纯金团簇类似,呈现一定奇偶振荡.混合团簇的电子性质,如最高占据分子轨道(HOMO),最低未占据分子轨道(LUMO),垂直电离势,垂直电子亲和能,Fermi能级和化学硬度等均与团簇空间结构和金、钯原子数之比直接相关.混合团簇中存在钯原子到金原子间的电荷转移,表明团簇中存在明显金钯间成键作用.分析团簇的电荷分布、前线轨道和化学硬度表明,金钯混合团簇对小分子如O2、H2和CO等的反应活性要强于纯金团簇.     

两种固定化金属螯合复合亲和膜色谱介质制备

以纤维素滤纸为基质,通过碱处理、环氧活化、偶联亚氨基二乙酸二钠、固定化Ｃｕ＾２＋后制得了大孔纤维素亲和膜。另外,在活化后的膜上通过共价交联覆盖上琼脂糖,制得了具有类似“三明治”结构且性能优于的复合亲和膜,装柱后分别制得固定化金属螯合亲和膜色谱柱。对两种亲和膜进行牛血清白蛋白等温吸附测定显示,两者的最大吸附量分别为１．１７ｍｇ／ｃｍ＾２和１．３０ｍｇ／ｃｍ＾２,与传统的琼脂糖凝胶类介质吸附量相当,表     

固定化金属螯合亲和膜色谱柱制备及纯化铜锌超氧化物歧化酶的研究

 以大孔纤维素滤纸为基质 ,通过碱处理、环氧活化、偶联亚氨基二乙酸二钠、固定化Cu2 +,装柱后制得固定化金属螯合亲和膜色谱柱。对Cu/Zn SOD粗品进行了纯化研究 ,将其比活从 645U/mL提高到 6882U/mL ,纯化倍数为 1 0 7,蛋白回收率为 92 3% ,活性回收率达 985%。设计了一种解决金属离子泄露问题的方案 ,将Cu2 +泄露量降至 86μg/L。     

Partition Affinity Ligand Assay (PALA)

In a competitive binding assay, the ligand to be quantified competes with a fixed amount of labeled ligand for the sites on a limiting amount of binding protein. The amount of label bound is therefore dependent on the ratio between native and labeled ligand. In a binding assay, one must separate the free ligands from bound. The better the separation, the higher the sensitivity of the assay. But effective methods are often laborious and time-consuming and thus we have developed a novel approach, the Partition Affinity Ligand Assay (PALA).     

Magnetic biospecific affinity adsorbents for immunoglobulin and enzyme isolation

Magnetic biospecific affinity adsorbents for immunoglobulin and enzyme isolation have been prepared. They were obtained by a “ post-magnetization” procedure involving a simple treatment of the various affinity gels with magnetic ferrofluid. The magnetic biospecific adsorbents tested include magnetic protein A-Sepharose for isolation of IgG antibodies, magnetic human serum albumin (HSA)-Sepharose for anti-HSA isolation, and magnetic 2′,5′-ADP for isolation of glucose-6-phosphate dehydrogenase from baker’s yeast and hemolyzates of human red blood cells. For the latter enzyme, a 11,000-fold purification was achieved in one step.     

Quantitative Structure—Activity Relationships in the Lithium and Sodium Affinities of n—Alkyl Fluorides

B3L YP/6-31 g(d,p)method was used to calculate the lithium and sodium affinities of n-alkyl fluoride. These affinities were found to obey the Holmes relationship, i.e.they correlate linearly with the quotient n/(n 1), where n is the number of carbon atoms in the alkyl chain. From the correlation the limiting values of lithium and sodium affinities for very long alkyl chain were predicted to be-153.3kJ/mol and -108.4kJ/mol,respectively.     

The estimation of electron affinities fromab initio 1s orbital energies

Summary It has been found that the electron affinities of alkoxy-radicals can be estimated using a correlation with the 1s orbital energy of the oxygen on the associated alkoxy-anion, EA=–0.64503 * (1s orbital energy) –351.58. The method assumes that the species of interest accepts the electron into an orbital which is localized on the oxygen.     

固定化铜离子亲和膜色谱柱吸附血红蛋白的研究

将纤维素滤纸进行碱处理及环氧活化、偶联亚氨基二乙酸、固定化铜离子等处理,并将其装入自制的色谱柱管,制得固定化铜离子亲和膜色谱柱。该柱可用于吸附血红蛋白(hemoglobin,Hb),吸附率可达到90%以上。考察了上样量、pH值、温度、上样速度等因素对固定化铜离子亲和膜吸附Hb的影响。实验结果表明,固定化铜离子亲和膜色谱柱吸附血红蛋白的最佳条件为：室温下实验,缓冲体系的pH值控制在6~8,上样速度0.5~1.0 mL/min,上样量为3.16~7.90 mg/g。     

亲和毛细管电泳技术在蛋白质-DNA相互作用研究中的应用

蛋白质-DNA的相互作用在决定细胞命运的许多过程中发挥重要作用,对蛋白质-DNA相互作用的分子机制研究有利于对基本生命过程的理解,为相关疾病的临床治疗及药物筛选提供理论指导。另一方面,利用一些已知的蛋白质-DNA相互作用可以帮助开发先进的生物工程和生命分析技术,为相关研究提供有力的技术支持。因此,建立灵敏、快速的分析方法用于表征蛋白质-DNA的相互作用十分重要。高效毛细管电泳(capillary electrophoresis, CE)技术因其超高的分离效率、极低的样品消耗与较短的分析时间等优势被广泛应用于化学、生命科学和环境科学等多个研究领域。其中,亲和毛细管电泳(affinity capillary electrophoresis, ACE)技术已经成为考察分子间相互作用的重要研究工具。这篇文章综述了亲和毛细管电泳技术自建立以来在蛋白质-DNA相互作用分析方面的研究进展,并对经典的研究工作进行了着重介绍,主要包括三方面的内容:(1)亲和毛细管电泳技术简介;(2)利用亲和毛细管电泳技术进行蛋白质-DNA相互作用的基础分子机制研究;(3)利用已知的蛋白质-DNA相互作用发展针对目标分子...     

Identification of Proteins Using Affinity Affi-Gel Simultaneously with Acrylamide Electrophoresis

Abstract

This work presents a method in which a desired protein may be separated from a biological protein preparation and identified by highly specific monoclonal antibody. The desired protein may be isolated from crude protein preparations by this method. The protein remains intact and stable throughout the procedure. This method utilizes common nonreducing conditions of polyacrylamide gel electrophoresis (PAGE), and Western Blot transfer of protein. This isolation of the desired protein can be accomplished for a microgram or tens of micrograms of material. The application of Western blot technique with monoclonal antibody permits the highest specificity in terms of identifying the target protein. In addition to identifying the target protein the method can isolate sufficient amounts for further characterization.     

Application of one-particle Green functions technique for calculation of vertical ionization potentials of closed-shell molecules described by CNDO/2 semiempirical Hamiltonian

A simple method of infinite summations of some dominant diagrams in the framework of the one-particle Green functions technique is suggested. This method for the calculation of the lowlying vertical ionization potentials of some simple closed-shell molecules described by CNDO/2 semiempirical Hamiltonian is applied. The obtained results are in quite-satisfactory agreement with the experimental values of the vertical ionization potentials measured by the photo-electron spectroscopy technique.     

核酸碱基互变异构体的结构、稳定性及其物理化学性质

核酸碱基是DNA及RNA分子的重要组成部分, 在基因遗传信息的传递方面起着主导作用. 核酸碱基存在多种互变异构体, 它们在DNA及RNA分子中主要以最稳定的异构体形式存在, 但是在气相或凝聚相中也有少量的其他异构体形式存在. 核酸碱基的稀有互变异构体往往能够引起碱基对的错配对, 这可能会导致DNA及RNA分子形成不规则的结构, 并进一步导致DNA或RNA双螺旋的自发突变. 因此, 对核酸碱基的互变异构体进行系统的研究, 有助于人们深入认识DNA和RNA分子的结构和性质. 国际上有很多研究小组已经通过实验和理论对核酸碱基互变异构体的结构、相对能量及其性质进行了研究. 本文对文献中有关核酸碱基互变异构体的实验和理论研究进行了综述. 在对前人研究进行归纳总结的基础上, 我们利用密度泛函计算对核酸碱基的互变异构体进行了排序, 得到的最优异构体结构参数和相对能量与实验值相比较为一致. 此外, 因为核酸碱基的物理化学性质可以为生物、化学、材料等方面的研究提供重要的基础性信息, 因此我们还对它们的电子亲和能、电离能、质子亲和能等研究进行了总结.     

Halogen versus halide electronic structure

Halide anions X-are known to show a decreasing proton affinity(PA),as X descends in the periodic table along series F,Cl,Br and I.But it is also well-known that,along this series,the halogen atom X becomes less electronegative(or more electropositive).This corresponds to an increasing energy of the valence np atomic orbital(AO) which,somewhat contradictorily,suggests that the electron donor capability and thus the PA of the halides should increase along the series F,Cl,Br,I.To reconcile these contradictory ...     

Superhalogens as Building Blocks of Super Lewis Acids

Lewis acids play an important role in synthetic chemistry. Using first-principle calculations on some newly designed molecules containing boron and organic heterocyclic superhalogen ligands, we show that the acid strength depends on the charge of the central atom as well as on the ligands attached to it. In particular, the strength of the Lewis acid increases with increasing electron withdrawing power of the ligand. With this insight, we highlight the importance of superhalogen-based ligands in the design of strong Lewis acids. Calculated fluoride ion affinity (FIA) values of B[C₂BNO(CN)₃]₃ and B[C₂BNS(CN)₃]₃ show that these are super Lewis acids.     

螯合金属离子亲和色谱法分离α-氨基酸和肽

以ＳｅｐｈａｄｅｘＧ１０为基质螯合二价铜离子的亲和色谱法分离α－氨基酸和肽，使之得以完全分离。对分离过程的原理进行了讨论。     

亲和色谱法的进展

概述了亲和色谱法分离机理、色谱填料及其应用的新进展,着重介绍了亲和固定相中配基发掘的新途径。全文包括66篇文献。     

亲和色谱纯化蛋白质新进展

通过对３５篇文献的综述,介绍了亲和色谱技术的新进展