核黄素与脱氧核糖核酸相互作用的电化学和光谱法研究

在实验条件接近人体生理环境的pH7.4的Tris-HCl缓冲溶液中,分别采用电化学方法、紫外光谱法及荧光法并利用中性红作电化学探针,研究了核黄素和小牛胸腺DNA的相互作用。随着DNA浓度逐渐增加,核黄素的峰电流减小,峰位正移;紫外光谱产生减色效应;核黄素的荧光发生猝灭以及核黄素和中性红竞争与DNA相互作用等,采用几种方法的实验结果都表明两者能发生嵌插结合;多种计算方法得到两者作用的结合位点数为1,结合常数达到105(mol/L)-1。     

Studies on Interaction Between Gallocyanine and DNA

IntroductionConsiderable attention has been focused onnew DNA- binding and DNA- modifying agents fromnatural ones to wholly synthetic designs due totheir usage as probes of deciphering the structureand the function of nucleic acids and as potentialchemotherapeutic agents[1— 4] . The application ofthose molecules must be based on the preciseunderstanding of the structural details about thebinding of the agents with the target molecule,double- helical DNA. The interaction of smallmolecules …     

奎宁与氯冉酸的胶束增敏荷移反应及其测定

提出了一种基于胶束增敏荷移反应测定奎宁的光度分析法。研究了在阳离子表面活性剂氯化十六烷基吡啶 (CPC)胶束体系中电子给体奎宁与电子受体氯冉酸之间的荷移反应产物的光谱性质。发现CPC对奎宁与氯冉酸的荷移反应络合物的光吸收有显著的增强作用 ,使络合物的表观摩尔吸光系数提高了 2 .5倍(λmax=5 2 0nm ,ε=3.6 4× 1 0 3 L·mol-1 ·cm-1 )。奎宁浓度在 2 0～ 80 0mg/L范围内符合比耳定律 ,r =0 9991。本方法用于片剂中奎宁含量的测定 ,其回收率为 97.3%～ 99.2 % ;5次测定的相对标准偏差为 1 .6 %～ 2 5 %。     

芦丁与DNA相互作用的电化学研究

研究了芦丁与 DNA在 p H 5.72条件下相互作用的电化学行为。 DNA的存在能导致芦丁氧化还原峰电流降低 ,峰电位基本不变。通过测定 DNA引入前后的一些电化学参数 ,推测芦丁与 DNA在该条件下结合生成了一种非电活性的超分子化合物。针对该类型体系 ,推导出了一系列的方程 ,求得该超分子化合物的组成为 1∶ 1 ,结合常数 β=2 .49× 1 0 5mol- 1·L。     

姜黄素与DNA相互作用的电化学性质

采用循环伏安法和差示脉冲伏安法,研究了姜黄素在DNA修饰玻碳电极上与DNA的相互作用.结果表明,姜黄素与DNA之间发生嵌插作用,形成了两种化合物DNA-2curcumin和DNA-curcumin,两者的表观结合常数分别为2.34×10^5L/mol和1.48 L/mol.     

氨基酸突变对GABAa受体结合能力的影响

采用同源建模技术构建了大鼠γ-氨基丁酸a型受体(GABAaR)模型, 并将氨基酸残基β157Tyr和β205Tyr突变为相应的突变受体模型. 使用分子对接方法计算了γ-氨基丁酸(GABA)与突变前后受体的相互作用. 对接计算结果显示, Tyr突变为Phe后, 两种突变受体的对接能量大幅提高, GABA生物活性降低; 当Phe的对位引入氟原子后, 对接能量与未突变受体相比更低. 另外, 与β205Tyr突变相比, 与配体距离较近的β157Tyr突变, 对受体与配体作用的影响更大.     

CdTe纳米晶与蛋白相互作用研究

当半导体纳米晶的直径小于其电子的玻尔直径时 ,半导体纳米晶对电子具有量子限域效应 ,其发光波长与纳米晶的尺寸相关 .与有机荧光分子相比 ,荧光半导体纳米晶具有以下优点 :(1 )其激发谱在吸收阈值以上几乎是连续的 ,利于多波长激发 ;(2 )高强荧光发射 ,谱峰窄 ,峰形对称 ;(3 )发射波长随着粒径的增大而有规律地红移 ,只需改变粒径即可获得多色发光 ;(4)纳米晶的发光稳定性好 ,不易被光分解和漂白 .因此 ,半导体纳米晶作为新一代荧光生物标记物已有研究[1～ 6] .荧光生物标记要求使用水溶性的纳米粒子 ,水相合成半导体纳米晶操作简便、重复…     

Spectroscopic Studies on the Interaction Between Troxerutin and Bovine Hemoglobin

The interaction of bovine hemoglobin (BHb) with troxerutin was investigated by UV–Vis absorption spectra and fluorescence spectra methods, circular dichroism spectra, and the freeze-fractured TEM methods. Results showed that troxerutin causes the fluorescence quenching of BHb through a static quenching mechanism. The binding constant K _A and number of binding sites n of troxerutin with BHb were obtained. Positive values of the thermodynamic parameters enthalpy change and entropy change indicate that the interaction between troxerutin and BHb is driven mainly by electrostatic interactions. This shows that the binding is spontaneous at the standard state since the change in the standard Gibbs energy value is negative. The average binding distance between the donor (BHb) and the acceptor (troxerutin) was assessed from the Förster theory. The present study suggests that the thermal stability of BHb is enhanced upon binding with troxerutin.     

核黄素的薄层荧光光谱电化学研究

光谱检测技术和电化学手段密切结合起来的光谱电化学方法,加上薄层池的整体快速电解,已成为化学工作者的重要研究手段［１］．目前紫外可见透射光谱检测方法多采用铂、金、石墨等的网栅为工作电极,对其透光度及强度均有一定要求,操作不便,池也不易清洗［２］;并且由...     

AnSBBR Applied to Organic Matter and Sulfate Removal: Interaction Effect Between Feed Strategy and Cod/Sulfate Ratio

A mechanically stirred anaerobic sequencing batch reactor containing anaerobic biomass immobilized on polyurethane foam cubes, treating low-strength synthetic wastewater (500 mg COD L^?1), was operated under different operational conditions to assess the removal of organic matter and sulfate. These conditions were related to fill time, defined by the following feed strategies: batch mode of 10 min, fed-batch mode of 3 h and fed-batch mode of 6 h, and COD/[SO₄ ^2?] ratios of 1.34, 0.67, and 0.34 defined by organic matter concentration of 500 mg COD L^?1 and sulfate concentrations of 373, 746, and 1,493 mg SO₄ ^2? L^?1 in the influent. Thus, nine assays were performed to investigate the influence of each of these parameters, as well as the interaction effect, on the performance of the system. The reactor operated with agitation of 400 rpm, total volume of 4.0 L, and treated 2.0 L synthetic wastewater in 8-h cycles at 30?±?1°C. During all assays, the reactor showed operational stability in relation to the monitored variables such as COD, sulfate, sulfide, sulfite, volatile acids, bicarbonate alkalinity, and solids, thus demonstrating the potential to apply this technology to the combined removal of organic matter and sulfate. In general, the results showed that the 3-h fed-batch operation with a COD/[SO₄ ^2?] ratio of 0.34 presented the best conditions for organic matter removal (89%). The best efficiency for sulfate removal (71%) was accomplished during the assay with a COD/[SO₄ ^2?] ratio of 1.34 and a fill time of 6 h. It was also observed that as fill time and sulfate concentration in the influent increased, the ratio between removed sulfate load and removed organic load also increased. However, it should be pointed out that the aim of this study was not to optimize the removal of organic matter and sulfate, but rather to analyze the behavior of the reactor during the different feed strategies and applied COD/[SO₄ ^2?] ratios, and mainly to analyze the interaction effect, an aspect that has not yet been explored in the literature for batch reactors.     

Spectroscopic and Electrochemical Studies of the Interaction Between Fuchsin Basic and DNA

Introduction DNAbiosensorsareacompletelynewtypeoftech nologicalconceptionsbyusingspecificaffinitybetween mattersinlivingbeingstodistinguishdirectlyand quicklysequence specificDNA[1].Withtherapidde velopmentofgeneticengineering,oneofthekeyissues needtobere…     

DNA与目标分子相互作用的预测性研究

以量化的分子结构参数和实验结果为依据, 运用模式识别技术、多元线性回归和人工神经网络研究了目标分子与DNA相互作用的主要影响因素, 建立了准确性较高的2个键合常数预测模型和1个作用模式预测模型. 初次量化的分子结构参数有21种, 经过筛选发现其中的10种参数对相互作用有显著影响. 研究结果可为抗癌药物的分子设计和筛选提供有价值的信息.     

光谱法研究硝苯柳胺与钥孔戚血蓝蛋白的相互作用

采用荧光光谱和紫外吸收光谱研究了不同温度下硝苯柳胺与钥孔戚血蓝蛋白(KLH)的相互作用.结果发现,KLH的特征荧光峰猝灭,硝苯柳胺对KLH的荧光猝灭机制属于静态猝灭;由Lineweaver-Burk方程计算出不同温度下硝苯柳胺与KLH之间的结合常数K分别为3.81×104 L/mol (25 ℃)和3.01×104 L/mol (37 ℃);由Van′t Hoff方程计算出ΔH和ΔS平均值分别为-15.09 kJ/mol和37.055 J mol -1 K -1,二者之间的作用力主要为静电作用力;该过程是一个熵增加、Gibbs自由能降低的自发分子间作用过程;根据Frster非辐射能量转移机制求得给体与受体间的结合距离r为4.61 nm,能量转移效率为0.0403.同步荧光光谱表明,硝苯柳胺能够被血蓝蛋白存储和转运, 但结合时对蛋白构象有一定影响.     

利福布汀与人血清白蛋白相互作用的光谱研究

用荧光光谱法和圆二色谱法研究了利福布汀(RB)与人血清白蛋白(HSA)的相互作用. 结果表明, RB与HSA之间的相互作用主要是疏水作用, 作用机制是静态猝灭与动态猝灭的结合. 其结合常数(Ka)在106数量级, 说明RB和HSA有很强的结合. 此外, 探讨了金属离子(Cu2+, Zn2+, Mg2+ 和Ca2+)对RB与HSA结合常数的影响. 同步荧光光谱和圆二色谱数据表明, RB可导致HSA的构象改变.     

VB6与不同CopC作用的光谱研究

在室温, pH 7.4, 10mmol?L-1 Hepes缓冲溶液条件下, 通过紫外差光谱,荧光光谱法研究了apoCopC、CuN-CopC与Ag+的结合性质,进一步研究了apoCopC、 CuN-CopC、CopC-AgC 和CuN-CopC-AgC 与 Vitamin B6 作用的超分子行为. 结果表明：在 apoCopC与Ag+剂量比为1:1时,Ag+可以占据apoCopC蛋白C端的Cu+ 结合位点,结合常数为(1.68±0.33)×104mol?L-1. apoCopC结合不同的金属离子后,与Vitamin B6结合位点数明显减少.     

β-环糊精和十二烷基硫酸钠包合作用的微量热法研究

环糊精（ＣＤ）和客体分子的选择性包合作用是现代化学研究中的一个重要课题，化学和药剂学应用中的分离分析、稳定作用、增溶作用及利用分子识别释放活性物质等都和它有着密切的关系．β－ＣＤ和十二烷基硫酸钠（ＳＤＳ）在毛细管电泳中有着广泛的应用［１］，β－ＣＤ＋...     

维生素B12与DNA相互作用的电化学研究

维生素B12与DNA相互作用的电化学研究;维生素B12; DNA; 循环伏安法; 紫外可见吸收光谱法     

卟啉/TiO2界面的相互作用研究

采用吸收光谱、荧光光谱和瞬态光伏技术研究了卟啉/TiO2体系的吸收光特性、荧光特性和光伏特性, 并研究了卟啉和TiO2之间的界面相互作用. 研究结果表明, 卟啉环在与钬原子结合前后与TiO2之间的作用不同, TiO2的粒径也影响界面的相互作用. 卟啉与粒径为10 nm的TiO2作用后, 能级发生了简并, 同时带隙发生了红移. 卟啉与粒径为56 nm的TiO2相互作用后只有特征吸收峰发生红移, 带隙和峰的数量几乎未发生变化. 这说明在粒径为10 nm的TiO2与卟啉的大π键之间出现了离域的相互作用, 这也被荧光光谱和瞬态光伏曲线所证实.     

Spectroscopic Electrochemical Studies of Interaction Between Fuchsin Basic DNA

Visible spectroscopic and electrochemical methods were used to study the interactions between DNA and fuchsin basic(FB). FB has an irreversible electro-oxidation peak in 5 mmol/L Tris-HCl buffer solution at pH = 7.4 on a glassy carbon electrode(GCE). After adding certain concentration of dsDNA, the oxidation peak current of FB decreases, but the peak potential hardly changs. The visible absorption spectroscopic study shows that the binding mode of FB to dsDNA is intercalative binding and electrostatic binding when the ratio of the concentration of dsDNA to FB is smaller than 0. 2, and a new substance, which produces a new absorption peak, is obtained via a covalent binding between dsDNA and FB apart from intercalative binding and electrostatic binding when the ratio of the concentration of dsDNA to FB is larger than 0. 2. The visible absorption spectra varies no longer when the ratio of the concentration of dsDNA to FB is larger than 1.5. A mean binding ratio of dsDNA to FB was determined to be 1.4: 1,suggesting that two complexes FB-dsDNA and FB-2dsDNA be formed. The interaction between FB and ssDNA was only electrostatic binding. The more powerful interaction of FB with dsDNA than with ssDNA may be applied for the recognition of dsDNA and ssDNA, and in DNA biosensor as hybridization indicator.     

促进剂与细胞色素C中赖氨酸残基相互作用的研究

促进剂与细胞色素ｃ中赖氨酸残基相互作用的研究曲晓刚，菊，周成立，陆天虹，董绍俊（中国科学院长春应用化学研究所，电分析化学开放实验室，长春，１３００２２）关键词细胞色素ｃ，促进剂，同步荧光光谱Ｈｉｌｌ小组［１］发现４，４＇－联吡啶能促进细胞色素ｃ（ｃｙ...