共查询到20条相似文献,搜索用时 46 毫秒
1.
可可碱与牛血清白蛋白作用光谱特性的研究 总被引:2,自引:0,他引:2
本文应用荧光光谱法研究了可可碱(TB)与牛血清白蛋白(BSA)相互作用的光谱特性。测定了18℃、30℃、40℃温度下的结合常数KA分别为1.68×10^4、1.58×10^4、1.45×10^4L/mol,结合位点数咒分别为1.04、1.03、1.03。实验结果表明:TB对BSA内源荧光的猝灭机理主要为静态猝灭;热力学参数探讨其相互作用机理,TB主要以静电力与BSA相互作用;研究了TB对BSA构象的影响,BSA的荧光主要源于色氨酸残基。同时研究了Cu^2+存在下TB与BSA的相互作用。 相似文献
2.
应用荧光光谱法研究了6-糠氨基嘌呤(KT)与牛血清白蛋白(BSA)相互作用的光谱特性。测定了16℃、28℃和39℃不同温度下的结合常数KA分别为:2.43×104、1.33×104、1.22×104L/mol,结合位点数n分别为:1.08、1.02、1.02。研究结果表明:KT对BSA内源荧光的猝灭机理主要为静态猝灭;探讨了相互作用机理,KT主要以静电作用与BSA相互作用;研究了KT对BSA构象的影响,表明BSA的荧光主要源于色氨酸残基,KT对BSA的构象有影响。 相似文献
3.
4.
《理化检验(化学分册)》2016,(11)
采用荧光光谱、紫外吸收光谱、同步荧光光谱和圆二色光谱研究了诱惑红(AR)与牛血清白蛋白(BSA)的相互作用;讨论了AR对BSA荧光的猝灭机理。荧光光谱与紫外吸收光谱表明,AR使BSA的荧光猝灭属于静态猝灭。根据热力学参数焓变(ΔH0)和熵变(ΔS0)可推断AR和BSA的相互作用力主要为静电引力。在298K,303K,308K温度下,两者间的结合常数分别为3.72×105,3.13×105,2.96×105L·mol-1,结合位点数为1.1。当AR与BSA的浓度比为1∶1时,两者间的结合距离为2.59nm。同步荧光光谱、三维荧光光谱和圆二色光谱研究结果表明,在结合过程中BSA的构象发生了变化。 相似文献
5.
本研究采用紫外和荧光光谱分析法研究了生理pH条件下盐酸异丙肾上腺素(HAI)与牛血清白蛋白(BSA)在不同温度(25℃和37℃)下的相互作用。实验结果表明,HAI使BSA紫外吸收峰增强,并使BSA的特征荧光峰猝灭,表明HAI与BSA形成结合物。HAI对BSA荧光猝灭机制为静态猝灭,属于单位点结合。25℃时两者之间的结合常数为7.41×103L·mol-1,ΔG为-22.10 kJ·mol-1,ΔH为25.86 kJ·mol-1,ΔS为940 J·mol-1。37℃时的结合常数为4.26×105L·mol-1,ΔH和ΔS与25℃时相同,ΔG为-33.41 kJ·mol-1。以上热力学参数表明HAI与BSA之间的结合属自发过程,两者之间的作用力以疏水作用为主。根据Fster非辐射能量转移理论计算出HAI与BSA间的结合距离为2.503nm。 相似文献
6.
在模拟生理条件下(pH=7.40),应用荧光光谱、吸收光谱和同步荧光光谱法探讨了不同温度下尼泊金乙酯钠(Ethylparaben Sodium,EPS)与牛血清白蛋白(Bovine Serum Albumin,BSA)相互作用的机制.荧光光谱和吸收光谱分别表明:尼泊金乙酯钠对BSA内源荧光有明显猝灭作用,属于静态猝灭,二者的猝灭作用是由于尼泊金乙酯钠与BSA形成基态复合物导致的.运用双对数方程求得291、310 K时的结合常数分别为3.23×106、3.63×105L·mol-1,结合位点数分别为0.99和0.84.运用热力学方程得出热力学参数(ΔH,ΔS),通过ΔH0,ΔS0可知二者之间的作用力主要是氢键或范德华力.同步荧光光谱表明尼泊金乙酯钠对BSA结构的构象会产生影响.本研究为EPS的毒理和生物学效应提供了重要的参考信息. 相似文献
7.
8.
孔雀石绿与牛血清白蛋白作用的光谱研究 总被引:2,自引:2,他引:0
应用荧光及紫外光谱法研究了孔雀石绿(MG)与牛血清白蛋白(BSA)相互作用的光谱特性。测定了16℃、26℃、36℃三个温度下的结合常数KA(7.066×103、4.638×103、1.338×103)和结合位点数n(1.2、1.1、1.0)。结果表明:MG对BSA内源荧光的猝灭机理主要为静态猝灭;MG主要以范德华力与BSA相互作用;同步荧光技术研究了MG对BSA构象的影响,表明BSA的荧光主要源于色氨酸残基,MG对BSA的构象有影响;利用F ster偶极-偶极非辐射能量转移理论,计算了三个温度下MG与BSA的作用距离(r16℃=3.30,r26℃=3.314,r36℃=3.58nm),表明MG对BSA的荧光猝灭中存在能量转移。 相似文献
9.
10.
运用荧光光谱和紫外-可见吸收光谱研究了雷尼替丁(Ran)与牛血清白蛋白(BSA)之间的相互作用.实验结果表明,Ran对BSA的内源荧光有较强的猝灭作用,猝灭机制为静态猝灭.测定了二者在不同温度下的表观结合常数KA,KA分别为5.64×105 L·mol-1(12℃)、5.38×105 L·mol-1(25℃)和5.15×105 L·mol-1(37℃),Ran与BSA以摩尔比1∶ 1结合.根据Frster非辐射能量转移理论,求出了37℃时给体(Ran)和受体(BSA)之间能量转移效率和结合距离分别为E=0.20和r=2.51nm.计算出的热力学参数表明,Ran和BSA之间的作用力主要是氢键和范德华力.利用同步荧光技术,研究了Ran对BSA构象的影响. 相似文献
11.
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%. 相似文献
12.
Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
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. 相似文献
13.
Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
14.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
15.
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. 相似文献
16.
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. 相似文献
17.
N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
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. 相似文献
18.
Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
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. 相似文献
19.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
20.
Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献