荧光法研究司帕沙星与白蛋白的作用

本文用荧光光谱法、分光光度法研究了水溶液中喹诺酮类药物司帕沙星与牛血清白蛋白 (BSA)、鸡蛋白 (CEA)的相互作用 ,求得它们间的结合常数为K鸡 =8 2 9× 10 6,K牛 =4 41× 10 7;结合位点数分别为n鸡=0 5 88,n牛 =0 793,并根据F rster非辐射能量转移机制 ,测定了司帕沙星与两种血清白蛋白相互结合时其给体 受体间距离 (R鸡 =1 99nm ,R牛 =2 0 9nm)和能量转移效率 (E鸡 =0 76 6 ,E牛 =0 714)。实验表明 ,随着温度升高 ,BSA及CEA的猝灭曲线斜率降低 ,证实了司帕沙星与BSA和CEA的相互结合作用为单一的静态猝灭过程 ,其作用机制属能量转移机制。通过两种血清白蛋白与抗菌药物司帕沙星结合反应 ,探讨了药物司帕沙星在生物体内与蛋白质的相互作用的生物学效应及其作用机理。     

牛血清白蛋白与金霉素结合反应的机制研究

以光谱技术与微量热技术相结合的方法研究水溶液中金霉素与牛血清白蛋白分子间结合作用的热力学性质 .荧光猝灭法测得该反应的结合常数K =2 .0 9× 10 5L/mol,结合位点数n =1.75 ,微量法测得反应的焓变△rHm=- 17.5 0kJ/mol;依据Forster非辐射能量转移机制 ,得到授体 受体间的结合距离 (r1=1.6 7nm ,r2 =1.4 6nm)和能量转移效率 (E1=0 .4 1,E2 =0 .6 6 ) .金霉素与牛血清白蛋白分子间有较强的结合作用 ,且结合力以疏水作用为主 .     

头孢克罗与人血清白蛋白相互作用机制

以光谱技术研究了人血清白蛋白 (HSA)与头孢克罗分子间结合作用机制。由Lineweave Burk双倒数作图法确定该反应的解离常数 Kd =1 2 2× 10 -4,用同步荧光技术考察了头孢克罗对人血清白蛋白物象的影响。依据Forster非辐射能量转移机制 ,得到给体 受体间的结合距离和能量转移效率。头孢克罗与人血清白蛋白以疏水作用为主。抗生素效力与能量转移效率和解离常数有关。     

盐酸表阿霉素与牛血清白蛋白相互作用的研究及药物在血清与尿样中含量的测定

应用荧光光谱法研究了盐酸表阿霉素与血清白蛋白之间的相互作用,求得它们之间的结合常数KA=2.342×10~4(t=25℃),KA=1.993×10~4(t=35℃),KA=1.638×10~4(t=45℃),以及金属离子对结合常数的影响,确定了药物与血清白蛋白之间的相互作用力,并根据Forster非辐射能量转移理论求出给体-受体间的结合距离r=4.25 nm和能量转移效率E=0.018。又进一步在生理条件下成功的测定了药物在血清与尿样中的含量。     

IBr分子的多光子电离谱的分析

本文用多光子电离的方法,观察了IBr分子高电子态(E)的2光子共振跃迁,结合Franck-Condon原理,从IBr分子的振动谱分析,首次得到IBr(E)态的转动常数B’_(?)-(0.0653±0.0003)cm~(-1).     

头孢哌酮与人血清白蛋白相互作用机制

用光谱方法研究人血清白蛋白(HSA)与头孢哌酮 (CPZ)分子间结合作用机制,头孢哌酮与β-内酰胺酶的亲和力。由Lineweave-Burk双倒数作图法确定了该反应的解离常数(15 ℃)K_d=1.10×10-4,(37 ℃)K_d=0.85×10-4。依据Frster非辐射能量转移机制,得到给体-受体间的结合距离和能量转移效率;确定了头孢哌酮与人血清白蛋白以静电作用为主。认为头孢哌酮对β-内酰胺酶稳定性与药物结构有关;抗菌活性和抗生素效力与能量转移效率和解离常数有关。同步荧光技术考察头孢哌酮对人血清蛋白构象的影响。     

计算光度法同时测定镧、铈、镨、钕

以二溴一氯-偶氮氯膦(DBC-CPA)为显色剂,并且在显色体系中加入不同量的EDTA-Na2P2O7作为竞争配位剂,使得4组分轻稀土组分间吸收光谱灵敏度的差别加大,从而增加了轻稀土混合物体系组分间吸收光谱的线性独立性,采用数值稳定性强的约束优化算法-可变容差法处理光谱数据,对不同深度比例的4组分轻烯土混合物体系(La^3 ,Ce^3 ,Pr^3 ,Nd^3 )的测定,取得了较为满意的结果.     

2,4-D对血清体系中性激素干扰机理研究

为了进一步了解环境内分泌干扰物对人体内性激素平衡的影响,实验选择2,4-D这种已被确认为环境内分泌干扰物的农药,研究了2,4-D、天然性激素（雌二醇、睾酮）加入人血清后体系紫外吸收光谱以及荧光光谱的变化,并通过温度与体系荧光强度的关系、计算扩散碰撞猝灭常数Kp等方法确定了2,4-D、天然性激素对血清组分的荧光猝灭机理,认为2,4-D可发生类似天然性激素和血清组分间的基态络合,并可能与天然性激素竞争占据血清蛋白的结合位点,由此干扰了生物体内正常的性激素水平。     

聚酯/无机杂化分子间键合作用及微结构相关性的光谱研究

采用FTIR,UV-Vis,WAXD和DSC手段,研究了分子间为非共价键化学结合的PCL／SiO2高分子-无机杂化透明材料组分间的键合型式;分子间特殊氢键相互作用行为与结晶性聚合物在杂化材料中的微结构相关性。结果表明,杂化体系中PCL高分子与SiO2无机组分间的键合,主要是依赖于杂化体系中较强的分子间氢键相互作用,其作用强度随无机相TEOS含量而变化。体系中氢键相互作用增加使PCL结晶高分子的相对结晶度下降,杂化材料的光学透明性提高。同时对体系中高分子-无机组分的微相分离尺度产生影响。     

金属离子Bi(Ⅲ)络合物体系的极谱法研究

在络合剂与金属离子浓度比固定条件下 ,改变溶液的pH值 ,用示差脉冲极谱技术研究金属离子Bi(Ⅲ ) 邻吡啶甲酸络合物体系 .根据实验得到的极谱峰电流和峰电位随溶液pH的变化 ,设计合适的金属络合物体系模型 .极谱实验络合物形成曲线 (ECFC)和理论络合物形成曲线 (TCFC)被用来检验金属络合物体系模型和优化络合物稳定常数 .含有极谱实验参数 (峰电位的移动和峰电流的变化 )的实验络合物形成曲线是特定金属络合物体系的特征函数 .理论络合物形成曲线的计算是基于金属络合物体系的质量平衡方程 .通过求解体系的质量平衡方程及拟合实验络合物形成曲线 ,用计算机分析程序CFC II优化得到金属络合物的稳定常数及金属离子的各种形态分布图 .计算机分析结果表明 ,在所研究的pH范围内 ,溶液中存在五种金属络合物 :MHL、ML、ML2 、ML3、ML3(OH) ,其稳定常数 (log β)分别为 7.5 2± 0 .15、7.48± 0 .0 6、13 .94± 0 .0 2、18.12± 0 .0 3、2 6.78± 0 .0 3 .     

Spectroscopic and nano-molecular modeling investigation on the binary and ternary bindings of colchicine and lomefloxacin to Human serum albumin with the viewpoint of multi-drug therapy

Combination of several drugs is often necessary especially during long-term therapy. The competitive binding drugs can cause a decrease in the amount of drug bound to protein and increase the biological active fraction of the drug. The aim of this study is to analyze the interactions of Lomefloxacin (LMF) and Colchicine (COL) with human serum albumin (HSA) and to evaluate the mechanism of simultaneous binding of LMF and COL to protein. Fluorescence analysis was used to estimate the effect of drugs on the protein fluorescence and to define the binding and quenching properties of drugs-HSA complexes. The binding sites for LMF and COL were identified in tertiary structure of HSA with the use of spectrofluorescence analysis. The analysis of fluorescence quenching of HSA in the binary and ternary systems show that LMF does not affect the complex formed between COL and HSA. On the contrary, COL decreases the interaction between LMF and HSA. The results of synchronous fluorescence, resonance light scattering and circular dichroism spectra of binary and ternary systems show that binding of LMF and COL to HSA can induce micro-environmental and conformational changes in HSA. The simultaneous presence of LMF and COL in binding to HSA should be taken into account in the multi-drug therapy, and necessity of using a monitoring therapy owning to the possible increase of the uncontrolled toxic effects. Molecular modeling of the possible binding sites of LMF and COL in binary and ternary systems to HSA confirms the spectroscopic results.     

头孢噻肟钠和氯霉素与牛血清白蛋白相互作用的荧光光谱分析

在pH=7.40 Tris-HCl缓冲溶液中,应用荧光光谱法分别研究了298,303,308 K时,头孢噻肟钠(CTX)、氯霉素(CHL)对牛血清白蛋白(BSA)荧光的猝灭反应.结果表明:药物与BSA的结合稳定常数Ka随温度增加而降低,两种药物对BSA的荧光猝灭皆为静态猝灭过程.标记竞争实验表明CTX、CHL在BSA中...     

Separate and simultaneous binding effects of aspirin and amlodipine to human serum albumin based on fluorescence spectroscopic and molecular modeling characterizations: A mechanistic insight for determining usage drugs doses

The binding of aspirin (ASA) and amlodipine (AML) to human serum albumin (HSA) in aqueous solution was investigated by multiple techniques such as fluorescence quenching, resonance light scattering (RLS), three-dimensional fluorescence spectroscopy, FT-IR and zeta-potential measurements in an aqueous solution at pH=7.4. For the protein-ligand association reaction, fluorescence measurements can give important clues as to the binding of ligands to proteins, e.g., the binding mechanism, binding mode, binding constants, binding sites, etc. Fluorescence spectroscopy showed that ASA and AML could quench the HSA fluorescence spectra, and this quenching effect became more significant when both ASA and AML coexisted. The results pointed at the interaction between HSA and both drugs as ternary systems decreasing the binding constant and binding stability of the HSA-drug complex as a binary system. Therefore, by reducing the amount of drugs transported to their targets, the free drug concentration of the target would be reduced, lowering the efficacy of the drugs. It was demonstrated that there exists antagonistic behavior between the two drugs when it comes to binding of HSA. Furthermore, the fluorescence results also showed that the quenching mechanism of HSA-drug complexes as binary and ternary systems is a static procedure. The number of binding sites of HSA-ASA, (HSA-AML)ASA, HSA-AML and (HSA-ASA) AML were 1.31, 0.92, 1 and 0.93, respectively. Due to the existence of the antagonistic action between ASA and AML, the binding distance r was reduced. The results of synchronous fluorescence and three-dimensional fluorescence spectra showed that the antagonistic action between ASA and AML would alter the micro-environment around Trp and Tyr residues. Moreover, the simultaneous presence of ASA and AML during binding to HSA should be taken into account in multidrug therapy, as it induces the necessity of a monitoring therapy owing to the possible increase of uncontrolled toxic effects. Molecular dynamic studies showed that the affinity of each of the drugs to HSA was reduced in the presence of significant amounts of the other. In the interaction of HSA with both drugs, the zeta potential of the ternary system is more negative than its binary counterpart. The zeta-potential results suggested induced conformational changes on HSA that confirmed the experimental and theoretical results.     

Interaction between Pazufloxacin and DNA Mediated by Copper(II) Ions

The influence of copper(II) ions on the binding of Pazufloxacin (PFLX), which is a forth generation quinolone antimicrobial agent, to calf thymus DNA (CTDNA) has been investigated by fluorescence, absorption spectroscopy and viscosity measurement. The results show that PFLX and Cu(2+) can form binary complex with mole ratio 2:1, PFLX and CTDNA can form complex mediated by Cu(2+). A ternary system of PFLX-Cu(2+)-DNA were proposed. The experimental results show that the PFLX binds to CTDNA by two kinds of binding modes, intercalative mode and groove binding mode.     

光谱法研究抗氧化剂、DPPH与人血清蛋白三元体系的作用

选取几种天然抗氧化剂杨梅素、桑色素、辣椒碱、甜菜碱作为研究对象,运用荧光光谱法、同步荧光光谱法以及三维荧光光谱法研究了几种抗氧化剂以及DPPH自由基与人血清蛋白相互作用,结果表明辣椒碱、甜菜碱、V_C不与人血清蛋白发生猝灭反应,杨梅素、桑色素、DPPH均能够与人血清蛋白发生猝灭反,反应均为形成了稳定复合物而导致的静态猝灭,通过疏水作用力与HSA结合,结合位点数均为1,主要结合位点在色氨酸基团附近,DPPH与人血清蛋白猝灭过程改变了人血清蛋白结构的疏水性,引起蛋白质构象发生变化,而杨梅素、桑色素与人血清蛋白相互作用未造成其构象发生了变化。运用荧光光谱法研究了几种抗氧化剂抑制DPPH直接损伤人血清蛋白的能力,杨梅素、桑色素、辣椒碱、甜菜碱、V_C对DPPH损伤HSA的抑制率分别为25%,18.30%,85.38%,4.02%和84.58%。根据分子结构分析辣椒碱主要通过清除DPPH自由基作用从而抑制其损伤人血清蛋白,根据二元体系反应结果可知杨梅素与桑色素三元体系反应过程中两种抗氧化剂与DPPH竞争结合位点,因此杨梅素、桑色素主要通过占据结合位点的方式抑制DPPH损伤人血清蛋白,而甜菜碱既不能占据结合位点也不能清除自由基,因而抑制能力最弱。分析表明几种天然抗氧化剂的抑制能力与其分子结构中主要官能团结构密切相关。     

荧光光谱法研究锌(Ⅱ)存在下诺氟沙星与牛血清白蛋白的结合作用

在模拟生理条件下,用荧光光谱法研究了诺氟沙星对牛血清白蛋白以及锌(Ⅱ)对诺氟沙星和牛血清白蛋白荧光光谱特性的影响。实验结果表明,诺氟沙星和锌(Ⅱ)都可以使牛血清白蛋白的荧光强度发生猝灭。根据荧光猝灭双倒数图计算诺氟沙星和牛血清白蛋白之间的结合常数为6.80×105,结合位点数为1.21。由此可见,诺氟沙星和牛血清白蛋白之间有很强的结合作用,这为诺氟沙星在体内被蛋白质储存和转运提供了条件。并且在锌(Ⅱ)存在下,诺氟沙星与牛血清白蛋白的结合作用有所增强。荧光猝灭双倒数图计算的结果表明,诺氟沙星和牛血清白蛋白之间的结合常数和结合位点数均随锌(Ⅱ)浓度的增大而增大。通过对锌(Ⅱ)、诺氟沙星和牛血清白蛋白的结合反应的研究,进一步探讨了诺氟沙星、锌(Ⅱ)在生物体内与蛋白质相互作用的机理。     

含CO2、DME和CH3OH等物质体系的汽液相平衡模型及相图

针对二甲醚生产过程中的汽液相平衡问题,本文提出了适于描述含CO2、DME和CH3OH体系的NRTL-PR模型组合,并以此模型计算了大量关于CO2-DME-CH3OH体系的三元VLE数据,绘制出几组等温、等压三元相图。可以认为,此模型得到的数据和相图能准确地反映含二甲醚体系的VLE关系,是实际生产工艺的研究与开发的重要基础。     

Computer simulation of the electronic structure and chemical bond in the ternary system Ti1−x AlxC

The electron energy structure of the ternary carbide system Ti-Al-C having an NaCl-type lattice is calculated by the local-coherent-potential method within the framework of multiple scattering theory. The cluster version of multiple scattering approximation is used to calculate the crystal potential. The electron energy structures of ternary and binary titanium carbide systems are compared in one approximation. The hybridized band of the ternary carbide system is 2.7 eV broader than that of the binary system, resulting from the formation of a covalent bond between Al and C. Metallic interaction takes place in the ternary system, its fraction increasing with the concentration of the 3p impurity. The energies of the chemical bond in the ternary and binary titanium carbide phases and in diamond are compared, and they are also compared with experiment. Fiz. Tverd. Tela (St. Petersburg) 39, 211–215 (February 1997)     

Solid-liquid equilibria for quaternary solid solutions involving compound semiconductors in the regular solution approximation

Liquidus equations for solid-liquid equilibria in quaternary systems involving compound semiconductors are presented in both thermodynamic (model-independent) and regular solution forms. A unified treatment is offered for terminal (doubly-doped binary compound, singly-doped ternary solution) as well as continuous series of solid solutions (mixing on one or both sublattices) which is facilitated by the choice of binary compounds as components in the solid. With the exception of the quaternary solid solution with mixing on both sublattices (i.e. Al_uGa_1?uP_vAs_1?v), the liquidus equations are generalizations of previous results for ternary systems. In the case of mixing on both sublattices, only three of the four possible liquidus equations are independent on account of the equilibrium among the four compound components. The required binary compound activities in the quaternary solution are deduced from a statistical treatment of a regular mixture of four kinds of atoms subject to the site restrictions of the zinc-blende lattice. The calculation of quaternary phase diagrams from binary and ternary data is discussed. Finally, it is found for the case of mixing on both sublattices that previous results, based on the decomposition of the quaternary solid solution into a binary regular mixture of ternary solids, are consistent with the present analysis.     

油酸甘油酯体系的低场核磁共振弛豫特性研究

甘油酯体系低场核磁共振（LF-NMR）弛豫特性的研究有助于脂质重构进程的快速监测及产物分析.本文主要对不同酯化度的单一或混合油酸甘油酯体系的LF-NMR弛豫特性进行了研究.结果表明,油酸甘油酯呈现三个弛豫峰;随酯化程度增加或温度升高,单组分和多组分弛豫时间均增大,各峰面积比例有一定改变,且酯化程度越高,弛豫时间的变化幅度越大;对二元和三元油酸甘油酯体系而言,随三油酸甘油酯（GTO）比例增至40%,单组分和多组分弛豫时间均增大,S₂₂峰面积比例增加,而S₂₃减小;三元混合体系的LF-NMR弛豫特性经主成分分析（PCA）后,混合体系在得分图上随GTO比例及二油酸甘油酯/单油酸甘油酯配比（GDO/GMO）的变化而呈规律性分布.