血清蛋白-荧光素复合物单扫极谱波与应用

在0．08mol／L的HAc中，荧光素与牛血清白蛋白(BSA)或人血清白蛋白(HSA)相互作用形成复合物。复合物使荧光素在-0．58V(vs．SCE)处的还原峰电流增大，峰电流的增大值与加入的BSA或HSA的浓度在一定的范围内呈线性关系。BSA在2—24μg／mL范围内呈线性关系，检出限为1μg／mL；HSA在2—22μg／mL范围里呈线性关系，检出限为0．8μg／mL。应用该法测定了人血清蛋白样品，结果令人满意。     

邻苯二酚与牛血清白蛋白的相互作用

采用荧光和紫外光谱法研究了邻苯二酚同牛血清白蛋白(BSA)的作用.邻苯二酚对BSA内源荧光猝灭机理为静态猝灭,两者之间生成了不发荧光的复合物.根据双对数方程计算了复合物的结合常数KA和结合位点数n.确定邻苯二酚与BSA只有一个结合位点(可能位于Site I).通过热力学参数得出邻苯二酚与BSA之间主要作用力是疏水作用.同步荧光的结果表明邻苯二酚改变了BSA的分子构象,使色氨酸残基的极性增加,酪氨酸残基的疏水性增强.     

溴甲酚绿分光光度法测定牛血清白蛋白

在pH 3.3的Britton-Robinson (B-R)缓冲溶液中, 对溴甲酚绿(BCG)与牛血清白蛋白(BSA)相互作用的吸收光谱进行了初步研究. 结果表明: BCG与BSA作用在室温下能迅速结合成复合物, 并且随着BSA的浓度增大, 在444 nm处的吸收峰降低, 618 nm处吸收峰升高并红移至628 nm. 在此波长下测定其复合物的吸光度, 其吸光度的增加值(ΔA)与BSA的质量浓度在8～260 μg/mL范围内呈良好的线性关系(r=0.9996), 检出限为4 μg/mL. 该方法应用于鲜奶粉和液态纯牛奶样品中总蛋白的测定, 回收率分别为92.7%, 95.5%, 结果与考马斯亮蓝G250法基本一致.     

偶氮胂Ⅲ-镝(Ⅲ)反射散射光度法测定蛋白质

研究了微晶石蜡吸萃蛋白质—偶氮胂Ⅲ-镝(Ⅲ)复合物的条件,并设计了固相反射散射分光光度直接测定石蜡相中牛血清白蛋白(BSA)的方法,所拟定的方法有较好的选择性,可以用于25—300μg／25mLBSA的测定．     

同步荧光光谱法结合分子对接研究染料木素与牛血清白蛋白之间的相互作用

在模拟生理条件下,通过荧光光谱法研究染料木素(Ge)与牛血清蛋白(BSA)间相互作用,在水溶液中Ge能够有效地猝灭BSA的荧光发射。考查了溶液p H、水浴温度、水浴时间等参数对于Ge猝灭BSA的影响,并且通过StemVolmer方程计算了Ge与BSA之间的结合类型、结合位点数和结合常数等参数。结果表明,Ge猝灭BSA的类型为静态猝灭,Ge与BSA可形成1∶1型非共价复合物。通过同步荧光光谱法结合分子对接研究了Ge与BSA间的作用情况,结果表明,氢键作用与疏水作用是Ge与BSA形成复合物的主要驱动力,Ge通过改变BSA中Trp134残基微环境的疏水情况猝灭BSA的荧光发射。     

稀土芦丁配合物的合成、表征及与血清白蛋白的相互作用

本文合成了稀土元素La，Pr，Gd和Dy的芦丁配合物，通过红外光谱、元素分析、热重-差热分析和摩尔电导率等方法对其进行了表征。同时在模拟动物体生理pH值条件下，用荧光光谱法研究了这4种配合物与人血清白蛋白(HSA)和牛血清白蛋白(BSA)的结合反应，结果表明：配合物对HSA和BSA都有较强的荧光猝灭作用。通过用Stern-Volmer方程处理实验数据发现：HSA和BSA与这4种配合物发生了反应,生成新的复合物，这种猝灭作用是由于分子内的非辐射能量转移而引起的静态猝灭。用Scatchard方程求出了形成复合物的结合常数KA和结合数n；并求得结合过程的热力学参数，初步确定配合物与血清白蛋白之间主要的作用力是氢键和Van der Waals力；同时用圆二色谱及同步荧光光谱法探讨了配合物对HSA和BSA构象的影响。     

聚乙烯醇与牛血清白蛋白的相互作用及对其构象的影响

在生理条件下, 使用凝胶过滤色谱、荧光光谱法、差示扫描量热分析和傅里叶变换红外光谱法(FTIR)研究了牛血清白蛋白(BSA)与聚乙烯醇(PVA)的相互作用. 实验结果表明, PVA与BSA结合形成复合物, 在其相互作用过程中, BSA色氨酸的发射荧光部分被猝灭, 但是, 相互作用并没有明显改变色氨酸的微环境; 差示扫描量热分析结果提示, BSA与PVA之间的相互作用可能破坏了PVA或BSA的分子内作用力; 用红外光谱法结合可增强分辨率的傅里叶去卷积技术和高斯曲线拟合技术共同用于对BSA与PVA复合物冻干粉中BSA酰胺Ⅰ带的定量分析, 发现冻干粉BSA分子中与分子间相互作用相关的β-折叠组分含量明显减少, 但是, 可用于衡量冻干状态蛋白质结构完整性的α-螺旋组分含量没有降低. 对冷冻干燥后样品中的可溶性BSA分析结果提示, PVA可以保护BSA冷冻干燥过程中的稳定性.     

蛋白质的偶氮胂Ⅲ-钡(Ⅱ)配合物光谱探针测定

研究了偶氮胂Ⅲ-Ba(Ⅱ)配合物与牛血清白蛋白(BSA)三体系复合物的吸收光谱,建立了一种新的蛋白质定量分析方法。研究发现,在表面活性剂阿拉伯树胶(gum arobic)存在下的酸性溶液中,偶氮胂Ⅲ-Ba(Ⅱ)配合物与BSA发生反应形成三元复合物,引起吸收光谱发生红移,吸收峰明显增高。摩尔吸光系数为ε611=1.01×106L.mol-1.cm-1,BSA的质量浓度在0~67 mg/L范围内服从比尔定律。用摩尔比法研究了此配合物与BSA的最大结合数为51。该法灵敏度高,选择性好,用于实际血清样品总蛋白的测定,与双缩脲法相关性良好。     

荧光光谱法研究4-硝基苯胺与牛血清白蛋白的相互作用

在模拟动物生理条件下利用荧光光谱法从分子水平上研究了4-硝基苯胺同牛血清白蛋白(BSA)的相互作用.4-硝基苯胺对BSA的荧光有较强猝灭作用.用Stern-Volmer方程和双对数方程分别处理实验数据发现BSA与4-硝基苯胺发生反应生成了新的复合物,猝灭机理以静态碎灭为主.根据双对数方程求出了不同温度下反应时复合物的形...     

BSA-羟基磷灰石可溶性复合物的FTIR光谱

利用富立叶变换红外光谱对水溶性牛血清白蛋白(BSA)羟基磷灰石复合物的组成及结构进行了研究.结果表明,其组成具有非化学计量的性质,且复合物中BSA与羟基磷灰石间存在相互作用.从而增加了羟基磷灰石在水中的溶解度.正是由于羟基磷灰石与蛋白质形成了水溶性的复合物,使羟基磷灰石在蛋白质结构的基质上成核和自组装成为可能,从而引起和促进了生物矿化过程.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.