纳米金与牛血清白蛋白作用的毛细管电泳研究

开展了针对微量纳米金与牛血清白蛋白相互作用的毛细管电泳研究, 测得二者的结合常数为28.6 L/μmol, 每个纳米金颗粒吸附约24个牛血清白蛋白分子. 结果表明, 牛血清白蛋白可改善并稳定纳米金的峰形, 二者作用时温育介质的pH以及电泳所用的缓冲溶液浓度对毛细管电泳(CE)效率有重要影响. 此法可推广到其它纳米颗粒的吸附研究中.     

碱性药物与人血清白蛋白结合参数的毛细管区带电泳/前沿分析

将毛细管区带电泳／前沿分析技术用于测定碱性药物ｖｅｒａｐａｍｉｌ（ＶＥＲ）和ｐｒｏｐｒａｎｏｌｏｌ（ＰＲＯ）与人血清白蛋白（ＨＳＡ）平衡体系中结合参数的研究。通过压力进样将药物白蛋白混合液引入石英毛细管电泳柱（３２ｃｍ×５０μｍｉ．ｄ．,聚丙烯酰胺涂渍柱）,在ｐＨ值为７．４、离子强度为０．１７的磷酸缓冲液及运行电压为１０ｋＶ的条件下,未结合的碱性药物的浓度可以通过电泳平台峰的高度定量,并且具有良好的线性关系（相关系数ｒ＝０．９９９）。     

毛细管电泳前沿分析法及分子模拟辅助研究牛血清白蛋白与荧光素钠的相互作用

应用毛细管电泳前沿分析法研究了荧光素钠与牛血清白蛋白(BSA)之间的相互作用,利用游离荧光素钠平台峰高度和荧光素钠浓度与峰高的线性关系得出游离以及与BSA结合的荧光素钠浓度,将不同浓度比的荧光素钠-BSA相互作用体系进行电泳,考察结合情况,进一步采用非线性方程和线性方程对数据进行拟合处理,得到了荧光素钠和蛋白质在286...     

毛细管电泳法对南方水牛奶乳清蛋白的分离和定量分析

利用毛细管区带电泳对广东省水牛乳乳清蛋白成分进行了分离和定量分析研究.采用1.2%的十四水合硼酸钠电泳缓冲液,对水牛奶乳清蛋白的四种主要组分α-乳白蛋白(α-La)、β-乳球蛋白(β-Lg)、牛血清白蛋白(BSA)、免疫球蛋白(IgG)进行了很好的分离,其迁移时间和峰面积的RSD分别小于1.5%和0.5%,加标回收率范围91%～102%.建立了基于毛细管区带电泳的分析方法,对牛乳及其乳制品中的乳清蛋白进行了快速分离和定量分析.     

重酒石酸去甲肾上腺素与牛血清白蛋白相互作用研究

本研究分别采用紫外分光光度法和亲和毛细管电泳法研究了重酒石酸去甲肾上腺素(NE-B)与牛血清白蛋白(BSA)的相互作用。紫外光谱结果表明,NE-B与BSA形成结合物而使BSA的紫外吸收增强。亲和毛细管电泳结果表明,37℃与25℃时时二者的结合常数(K)为分别为K_1=1.03×10~4L·mol~(-1),K_2=9.14×10~3L·mol~(-1)。由热力学参数计算结果可知,NE-B与BSA之间的结合属自发过程,二者之间的作用力以疏水作用为主。     

第八届全国微纳生物化学分离分析会议（CMSB2008）（原全国毛细管电泳及相关微纳分离分析学术报告会）第一轮通知

国际毛细管电泳界早已在多年前将国际毛细管电泳学术报告会(HPCE)改名为国际微型生物化学分离分析学术报告会(简称MSB)。为和国际学术界接轨,根据我国毛细管电泳界同仁的建议,现决定自2008年起将全国毛细管电泳会(CCE)改名为全国微纳生物化学分离分析会议(CMSB),第八届全国微纳     

第八届全国微纳生物化学分离分析会议（CMSB 2008）（原全国毛细管电泳及相关微纳分离分析学术报告会）第一轮通知

国际毛细管电泳界早已在多年前将国际毛细管电泳学术报告会(HPCE)改名为国际微型生物化学分离分析学术报告会(简称MSB)。为和国际学术界接轨,根据我国毛细管电泳界同仁的建议,现决定自2008年起将全国毛细管电泳会(CCE)改名为全国微纳生物化学分离分析会议(CMSB),第八届全国微纳     

第八届全国微纳生物化学分离分析会议（CMSB 2008）（原全国毛细管电泳及相关微纳分离分析学术报告会）第一轮通知

国际毛细管电泳界早已在多年前将国际毛细管电泳学术报告会(HPCE)改名为国际微型生物化学分离分析学术报告会(简称MSB)。为和国际学术界接轨,根据我国毛细管电泳界同仁的建议,现决定自2008年起将全国毛细管电泳会(CCE)改名为全国微纳生物化学分离分析会议(CMSB),第八届全国微纳     

免疫亲和毛细管电泳的研究进展

免疫亲和毛细管电泳方法结合了免疫分析的高特异性和毛细管电泳分离的高效、快速、样品用量少等优点,是复杂样品中特定组分分析的重要方法之一。激光诱导荧光检测器的使用以及毛细管电泳分离前免疫预富集过程的引入,可以进一步提高分析测定的灵敏度,使其能够用于痕量物质的高灵敏测定。本文结合作者所在课题组的工作,对免疫亲和毛细管电泳的两种主要模式,即均相的毛细管电泳免疫分析(CEIA)和非均相的免疫亲和毛细管电泳(IACE)的研究进展进行了综述。     

毛细管电泳法研究牛血清白蛋白与盐酸异丙肾上腺素的相互作用

本研究分别采用区段-区段动力学毛细管电泳法(Plug-Plug Kinetic Capillary Electrophoresis,ppKCE),及以药物为添加剂的亲和毛细管电泳法(Affinity Capillary Electrophoresis,ACE)对盐酸异丙肾上腺素(Hydrochloric Acid Isoproterenol,HAI)与牛血清白蛋白(Bovine Serum Albumin,BSA)的结合作用进行研究。实验结果显示,ppKCE法可同时测得HAI与BSA相互作用体系的结合速率常数kon和离解速率常数koff分别为163.60L·mol-1·s-1、3.50×10-2±0.95×10-2s-1(n=3)。ppKCE法和ACE法测得HAI与BSA的结合常数Kb分别为4.67×103 L·mol-1、6.02×103 L·mol-1,两种方法所得结果能够较好吻合。证明毛细管电泳法在药物-蛋白相互作用研究领域的可靠性,可用于测定药物与蛋白的相互作用,从而用于新药筛选研究。     

高效迎头分析法测定药物-人血清白蛋白混合液中游离药物浓度

 用高效迎头分析法 (HPFA)测定了药物 人血清白蛋白 (HSA)混合液中游离药物的浓度。样品溶液不经任何处理直接进样到装有内表面反相固定相的色谱柱中 ,用 67mmol/L磷酸盐缓冲液 ( pH 7 4 ,I =0 17mol/L)作流动相。当进样体积足够大时 ,游离药物以平顶峰的形式被洗脱出来 ,平顶峰区域洗脱液中的药物浓度等于样品溶液中游离药物的浓度。收集平顶峰区域的洗脱液 ,然后将一定体积的洗脱液注入到反相色谱柱中 ,测定游离药物的浓度。用该法测定酮基布洛芬 HSA和头孢哌酮 HSA两种混合液中游离药物的浓度。     

Interception of Deaminatively Generated Benzyl Carbenium Ions by Acetone

Essentially free benzyl carbenium ions were generated via protonation of phenyldiazomethane with benzoic acid in acetone. Interestingly, no proton transfer occurred below -20 degrees C. After protonation and dediazoniation of the diazoalkane at -20 degrees C, the solvent was found to intercept the deaminatively generated carbocations to yield initially the corresponding O-benzyl oxonium ion and benzyl benzoate. The onium ion, however, was labile under the reaction conditions, and decomposed into a cascade of products whose concentrations as a function of time were used to trace the reaction pathway. Thus, the O-benzyl oxonium ion reacted with benzoate ion to yield (2-benzyloxy)isopropyl benzoate; subsequent decomposition of this O-benzyl-O-benzoyl ketal produced 2,2-dibenzyloxypropane (a dibenzyl ketal), 2-benzyloxypropene, and benzyl alcohol. In a related study, benzyl cations were generated via thermolyses of N-benzyl-N-nitroso-O-benzoyl hydroxylamine at 0 and -70 degrees C. The product distributions were found to be temperature-dependent and different from that in the PhCHN(2) + PhCO(2)H case.     

Interaction of halide and carboxylate ions with 4,5-diacetamidoacridine-9(10H)-one: thermodynamics of association and deprotonation events

4,5-Diacetamidoacridine-9(10H)-one was prepared, and its interactions with halide and benzoate anions were studied using a combination of NMR, fluorescence, and isothermal titration calorimetry experiments. Whereas chloride and bromide exhibited simple association, both fluoride and benzoate exhibited initial entropy-driven association followed by an enthalpically favorable deprotonation of the receptor by a second equivalent of the anion.     

UV-absorbance detector for HPLC based on a light-emitting diode

A flow-through optical absorption detector for HPLC was constructed using a novel deep-UV light-emitting diode as radiation source with a peak emission wavelength of 255 nm. For measuring the transmitted intensity (a property correlated to Transmittance) a special UV-sensitive photodiode was employed. Besides the power source, no optical or electronic components other than an inexpensive operational amplifier and a few passive components were necessary. The performance of the detector was tested with three substances, namely nitrobenzene, benzoic acid and methyl benzoate, which were separated by gradient elution using an acetonitrile/water mixture and tetrabutylammonium hydrogensulfate as pH-buffer. Calibration curves for concentrations between 1.6 microg.mL(-1) and 400 microg.mL(-1) (nitrobenzene) and 8 microg.mL(-1) and 2.5 mg.mL(-1) (benzoic acid and methyl benzoate) were determined and coefficients of determination, r(2), of 0.9945, 0.9972 and 0.9996 were obtained for quadratic curve fits for the 3 compounds respectively. Relative standard deviations (n = 7) for peak areas were determined as 0.35% (nitrobenzene, 80 microg.mL(-1)), 0.27% (benzoic acid, 400 microg.mL(-1)) and 0.83% (methyl benzoate, 200 microg.mL(-1)). The lower limits of detection were found to be 750 ng.mL(-1), 5.8 microg.mL(-1) and 12 microg.mL(-1) for nitrobenzene, benzoic acid and methyl benzoate respectively.     

Determination of the cis-trans isomerization barrier of enalaprilat by dynamic capillary electrophoresis and computer simulation

Dynamic capillary electrophoresis (DCE) and computer simulation of the elution profiles with the stochastic model has been applied to determine the isomerization barriers of the angiotensin converting enzyme inhibitor enalaprilat. The separation of the rotational cis-trans isomeric drug has been performed in an aqueous 20 mM borate buffer at pH 9.3. Interconversion profiles featuring plateau formation and peak broadening were observed. To evaluate the rate constants k(cis-->trans) and k(trans-->cis) of the cis-trans isomerization from the experimental electropherograms obtained by dynamic capillary electrophoresis, elution profiles were analyzed by a simulation with iterative convergence to the experimental data using the ChromWin software which requires the total migration times of the individual isomers t(R), the electroosmotic break-through time t(0), the plateau height h(plateau), the peak widths at half height of the individual isomers w(h), as well as the peak ratio of the isomers as experimental data input. From temperature-dependent measurements between 0 degrees and 15 degrees C the thermodynamic parameters Delta G, Delta H and Delta S, the rate constants k(cis-->trans) and k(trans-->cis) and the kinetic activation parameters Delta G*, Delta H*, and Delta S* of the cis-trans isomerization of enalaprilat were obtained. From the activation parameters the isomerization barriers at 37 degrees C were calculated to be Delta G* (trans-->cis) = 87.2 kJ.mol(-1) and Delta G*(cis-->trans) = 91.9 kJ.mol(-1).     

Capillary electrophoresis study of human serum albumin binding to basic drugs

Summary The applicability of capillary electrophoresis/frontal analysis (CE/FA) for determining the binding constants of the drugs propranolol (PRO) and verapamil (VER) to human serum albumin (HSA) was investigated. After direct hydrodynamic injection of a drug-HAS mixture solution into a coated capillary (32 cm × 50 μm i.d.), the basic drug was eluted as a zonal peak with a plateau region under condition of phosphate buffer (pH 7.4; ionic strength 0.17) at 12 kV positive running voltage. The unbound drug concentrations measured from the plateau peak heights had good correlation coefficients,r>0.999. Employing the Scatchard plot, the Klotz plot and nonlinear regression, the drug protein binding parameters, the binding constant and the number of binding sites on one protein molecule, were obtained. The binding constant obtained was compared to a reported equilibrium dialysis result and they are basically in good agreement.     

Direct calculation of interconversion barriers in dynamic chromatography and electrophoresis: Isomerization of captopril

Dynamic capillary electrophoresis (DCE) and direct calculation of the rate constants of isomerization has been applied to determine the cis-trans isomerization barriers of the angiotensin-converting enzyme inhibitor captopril. The separation of the rotational cis-trans isomeric drug has been performed in an aqueous 50 mM borate buffer at pH 9.3. Interconversion profiles featuring plateau formation, peak-broadening, and peak coalescence were observed. To determine the rate constants of the forward and backward reaction (k(cis-->trans) and k(trans-->cis)) of the isomerization process in dynamic capillary electrophoresis, a novel straightforward calculation method using the experimental parameters plateau height, h(plateau), peak width at half height w(h), the total migration times of the cis-trans isomers t(R) and the electroosmotic break-through time t(0) as well as the peak ratio of the cis-trans isomers is presented for the first time. From temperature dependent measurements the rate constants k(cis-->trans) and k(trans-->cis) and the kinetic activation parameters DeltaG( not equal), DeltaH( not equal), and DeltaS( not equal) of the cis-trans isomerization of captopril were obtained. From the activation parameters the isomerization barriers of captopril at 37 degrees C under basic conditions were calculated to be DeltaG( not equal) (cis-->trans) = 90.3 kJ.mol(-1)and DeltaG( not equal) (trans-->cis) = 90.0 kJ.mol(-1*).     

Interaction of sodium benzoate with trypsin by spectroscopic techniques

The toxicity of sodium benzoate to trypsin was investigated by fluorescence spectroscopy, synchronous fluorescence spectroscopy, UV-visible absorption spectroscopy and circular dichroism (CD) spectroscopy under mimic physiological conditions. Sodium benzoate could unfold trypsin by decreasing the β-sheet structure, which leads to more exposure of internal amino acid groups and the obvious intrinsic fluorescence quenching with the rising concentration of sodium benzoate. The results of spectroscopic measurements indicated that sodium benzoate changed the internal microenvironment of trypsin and induced the alteration of the whole molecule, which were performed toxic effects on the organism. Trypsin and sodium benzoate interacted with each other to produce a substance by van der Waals forces and hydrogen bond, the model of which was shown by AutoDock software.     

超高效液相色谱法测定儿童指画印泥中柚皮苷和苯甲酸地那铵

儿童指画印泥样品用甲醇与0.02mol·L^-1磷酸二氢钾溶液以体积比3∶7组成的混合液超声萃取20min,冷却至室温,于16 000r·min^-1转速下离心15min,取上清液过0.22μm过滤膜过滤,采用超高效液相色谱法测定滤液中柚皮苷和苯甲酸地那铵的含量。以C18色谱柱为分离柱,用乙腈和pH 4.3的0.02mol·L^-1磷酸二氢钾溶液以不同比例混合的溶液为流动相进行梯度洗脱,用二极管阵列检测器测定。柚皮苷和苯甲酸地那铵的质量浓度均在0.1~5.0mg·L^-1内与其对应的峰面积呈线性关系,检出限(3S/N)依次为0.75,1.15mg·kg^-1。以空白样品为基体进行加标回收试验,所得回收率为73.5%~104%,测定值的相对标准偏差(n=6)为4.2%~6.6%。