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1.
5,7-二羟基黄酮与牛血清白蛋白相互作用的研究   总被引:1,自引:0,他引:1  
黄娟  陈秋云 《光谱实验室》2007,24(6):1095-1098
用荧光光谱(FS)和紫外光谱(UV)法研究了5,7-二羟基黄酮与牛血清白蛋白之间的相互作用.实验结果表明,5,7-二羟基黄酮与BSA形成基态复合物导致内源荧光淬灭,淬灭机理主要为静态淬灭.该反应的结合常数4.16×107 L/mol,结合位点数n=1.5;并用同步荧光技术考察了5,7-二羟基黄酮对BSA构象的影响.  相似文献   

2.
应用荧光光谱法研究了分子内电荷转移荧光探针1-酮-2-(对二甲氨基苯亚甲基)-四氢萘(KDTN)与牛血清白蛋白(BSA)的相互作用。研究表明,KDTN能与牛血清白蛋白形成稳定的络合物从而猝灭BSA的荧光,疏水作用是结合反应的主要作用力,二者的结合常数为3.2742×104L.mol-1,结合位点数n=0.9389(30℃时)。同时考察了KDTN的加入对BSA构象的影响。  相似文献   

3.
荧光光谱法研究二溴羟基卟啉与蛋白质的结合作用机理   总被引:8,自引:1,他引:7  
应用荧光光谱法研究了meso-四(3,5-二溴-4-羟基苯基)卟啉[T(DBHP)P]与牛血清白蛋白(BSA)之间的结合反应,基于T(DBHP)P对BSA内源荧光的猝灭机理,测定了两者之间在不同温度下的结合常数,温度为27℃时,荧光猝灭法测得反应的结合常数为K=1.30×106L.mol-1,温度为48℃时,K=6.32×105L.mol-1,结合常数随温度升高而减小,由此判定该猝灭类型为静态猝灭。根据F rster非辐射能量转移理论,确定了T(DBHP)P与BSA之间的能量转移效率E=0.91,能量给体(BSA)与受体[T(DBHP)P]之间的结合距离r=2.39 nm<7 nm,符合非辐射能量转移条件。依据热力学参数ΔG<0,ΔH<0,ΔS>0确定了T(DBHP)P与BSA之间的作用力主要是静电引力。同时,利用同步荧光光谱,考察了T(DBHP)P对BSA构象的影响,结果发现,T(DBHP)P的加入使BSA构象发生变化,BSA内部残基所处环境的疏水性降低。  相似文献   

4.
采用荧光光谱研究3-羟基-6-[(4-羧基苯基)偶氮]-苯甲酸(HCPAB)与牛血清蛋白(BSA)的相互作用.通过测定298K和310K下HCPAB与BSA的荧光猝灭光谱,计算得到荧光猝灭常数、反应的结合常数、结合位点数及热力学参数,得出这种荧光猝灭机理符合静态猝灭;由Foerster能量转移机理,计算了当BSA与HCPAB比例为1∶1时分子间距离r=3.18nm和能量转移效率E=0.23,并由同步荧光光谱显示HCPAB与BSA的结合位点更接近于色氨酸.  相似文献   

5.
合成了四(对甲氧基苯基)钐卟啉,利用荧光光谱法研究了四(对甲氧基苯基)钐卟啉与牛血清白蛋白(BSA)的相互作用。结果表明四(对甲氧基苯基)钐卟啉对BSA的荧光有较强的猝灭作用,属于静态荧光猝灭,由实验数据求得猝灭速率常数K_q=1.3842×10~(13)L·mol~(-1)·s~(-1)、结合常数K_△=3.4610×10~4L·mol~(-1)、结合数n≈1。  相似文献   

6.
利用荧光光谱法研究了四环素和牛血清白蛋白(BSA)分子间的相互作用,在BSA荧光最强的pH=6.5的醋酸缓冲溶液中测定了结合常数(在19℃,7.61 ×103L·mol-1)和结合点数(n=0.88).研究表明:四环素可猝灭BSA的荧光,是静态猝灭过程.同时四环素的荧光也被BSA增敏并随着BSA的浓度的增加而增加.用同步扫描法讨论了四环素对BSA构象的影响和作用点位.  相似文献   

7.
在不同温度下,采用荧光光谱,紫外-可见吸收光谱研究了虎杖苷与牛血清白蛋白(BSA)的相互作用。虎杖苷对BSA的荧光有较强的猝灭作用。根据292K和311K时虎杖苷对BSA的荧光猝灭作用,利用Stern-Volmer方程及双倒数方程处理实验数据,表明虎杖苷对BSA的荧光猝灭作用属于动态猝灭过程,根据Foerster非辐射能量转移理论计算出了虎杖苷与BSA间的结合距离r=3.61nm,结合常数(Kb)分别为5.189×105L·mol-1(292K),1.382×105L·mol-1(311K)及对应温度下的热力学参数。实验结果表明二者主要靠疏水作用力结合,采用同步荧光光谱探讨了虎杖苷对BSA构象的影响。  相似文献   

8.
盐酸四环素属于抗生素类, 目前有关盐酸四环素和牛血清白蛋白二级结构的影响及作用机理报道较少。在模拟生理条件下,采用荧光光谱法、三维荧光光谱法、紫外-可见光谱法、圆二色谱法和傅里叶红外光谱法以及分子对接模拟法,研究了盐酸四环素与牛血清白蛋白(BSA)之间的相互作用。荧光光谱表明,盐酸四环素能有效猝灭BSA的内源荧光,猝灭机制属静态猝灭,通过Stern-Volmer方程计算结合常数Ka为2.813×105 L·mol-1(298 K)。根据Vant’s Hoff方程确定结合过程中的热力学参数ΔS=-151.1 J·mol-1·K-1、ΔH=-76.09 kJ·mol-1 两者之间作用为氢键和范德华力。同步荧光光谱、紫外光谱、三维荧光光谱、红外光谱、圆二色谱结果证明盐酸四环素能够改变BSA的二级结构和微环境。根据Föster’s非辐射能量转移理论,盐酸四环素与BSA结合距离为0.49 nm。希尔系数(nH)值小于1,表明盐酸四环素与BSA结合后存在药物间协同作用。圆二色谱(CD)定量测定了盐酸四环素与BSA作用前后的二级结构含量:α-螺旋含量增加了9.16%(1:1)。分子对接模拟表明盐酸四环素通过氢键、疏水作用和范德华力等多种作用力结合在BSA的site Ⅰ(亚域ⅡA)。本研究有助于了解盐酸四环素与BSA的作用机制,也有助于理解盐酸四环素对蛋白质在储运过程中功能的影响。  相似文献   

9.
在模拟生理条件下应用荧光光谱和紫外-可见吸收光谱技术研究了牛血清白蛋白(BSA)与对硝基苯酚的相互作用.通过修正Stern-Volmer方程求算出在不同温度下(304,307,310K)的淬灭常数为1.186,1.030,0.940×105 L·mol-1,证实了BSA与对硝基苯酚相互结合作用为单一的静态猝灭过程,并且得到对硝基苯酚与BSA相互作用的热力学参数△H0和△S0分别为-28.061kJ·mol-1和-14.331J·mol-1·K-1,推出两者的相互作用以氢键为主.根据非辐射能量转移理论,计算出对硝基苯酚与BSA相互结合时其供体-受体间的结合距离(r=5.94nm)和能量转移效率(E=0.09).  相似文献   

10.
采用荧光、紫外及红外光谱法研究了头孢他啶与牛血清白蛋白(BSA)的结合反应.头孢他啶对BSA的色氨酸残基和酪氨酸残基均具有猝灭作用,其猝灭机理为静态猝灭,两者之间形成新的复合物是导致BSA荧光猝灭的主要原因.获取了复合物的结合常数(298K:1.27×10~4L·mol~(-1);310K:1.33×10~41·mol~(-1)).BSA Ⅱ A结构域的site I位点是其唯一可能结合位点.同步荧光光谱表明头孢他啶造成BSA的酪氨酸残基的极性增强.红外光谱表明头孢他啶引起了BSA二级结构的改变,使其α-螺旋含量降低.  相似文献   

11.
Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.  相似文献   

12.
A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.  相似文献   

13.
A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.  相似文献   

14.
The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.  相似文献   

15.
16.
Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·104 Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.  相似文献   

17.
A transient suppression method for piezoelectric ceramic transducer is presented. By adding some special pedestal pulses to the original transmitted signal, the transient effects in the output of the transducer can be just precisely transmission by use of a narrowband transducer. canceled, thereby achieving the broadband The experimental results show that the transient responses of the sinusoid pulses and coded signals are suppressed successfully and the acoustic waveforms radiated into the surrounding water are improved significantly.  相似文献   

18.
We experimentally demonstrate amplitude squeezed soliton utilizing intensity-dependent self-phase modulation in an asymmetric Sagnac interferometer.The system.whose components are connected via ferrule connector/physical connection(FC/PC)fiber connectors,constitutes all-fiber configuration to generate squeezed soliton.Soliton amplitude reduction measured by homodyne detection is near 4.0 dB below the shot-noise level.Optimal squeezing fields in both simple and compact all-fiber configuration are obtained.  相似文献   

19.
The(2 1)-dimensional nonlinear Schr(o)dinger(NLS)equation with spatially inhomogeneous nonlinearities is investigated,which describes propagation of light in(2 1)-dimensional nonlinear optical media with inhomogeneous nonlinearities.New types of optical modes and nonlinear effects in optical media are presented numerically.The results reveal that the regular split of beam can be obtained in (2 1)-dimensional nonlinear optical media with inhomogeneous nonlinearities,by adjusting the guiding parameter.Furthermore,the stability of beam regular split is discussed numerically,and the results reveal that the beam regular split is stable to the finite initial perturbations.  相似文献   

20.
In the real-world application of face recognition system, owing to the difficulties of collecting samples or storage space of systems, only one sample image per person is stored in the system, which is so-called one sample per person problem. Moreover, pose and illumination have impact on recognition performance. We propose a novel pose and illumination robust algorithm for face recognition with a single training image per person to solve the above limitations. Experimental results show that the proposed algorithm is an efficient and practical approach for face recognition.  相似文献   

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