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通过紫外-可见光谱、荧光光谱、同步荧光光谱、圆二色谱、衰减全反射红外光谱、负染-透射电镜、等温滴定微量热等实验方法系统地探讨了咪唑型离子液体与牛血清蛋白(BSA)的缔合特性.结果发现,离子液体[Bmim]Cl的加入使得BSA的紫外吸收强度增加,同时也会导致其荧光猝灭,并且这种猝灭是静态猝灭.同步荧光的研究结果表明,[Bmim]Cl分子可与蛋白质中接近色氨酸残基的区域发生相互作用,使蛋白质的构象和内部的疏水结构发生改变;负染色法透射电镜直观地显示了加入离子液体后形成的蛋白质-离子液体复合物结构逐渐变大;圆二色谱和衰减全反射红外光谱表明:在离子液体与BSA缔合过程中,离子液体的加入使得BSA二级结构中的α-螺旋和β-折叠的含量降低,从而引起蛋白质二级结构的变化;表面张力法和等温滴定微量热法进一步证实上述缔合作用为静电作用和疏水作用共同作用的结果,但离子液体的烷基链与BSA疏水内腔之间的疏水作用是离子液体与BSA缔合的主要驱动力. 相似文献
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建立了一种多肽免疫抗原偶联的双监测法,获得一种操作简便、成功率高、适用范围广的碳二亚胺偶联法,并应用于多种肿瘤相关多肽标志物的免疫抗原制备。以合成多肽SP0104为标准品,牛血清白蛋白(BSA)为载体蛋白,碳二亚胺(EDC)为偶联剂,对加样顺序、投料比、偶联时间等关键条件进行考察,采用UV和SDS-PAGE对反应产物进行联合监测,以偶联比和偶联率联合评价反应条件。加样顺序为多肽和载体蛋白先混合再加到碳二亚胺中,三者质量比为1∶1∶1,偶联时间为12 h,偶联比在4∶1~12∶1之间,偶联率在9%~20%之间,所得SP0104多抗效价达到1∶80 000,MALDI-TOF质谱分析证实该抗体准确捕获目标抗原。用优化的偶联方法制备多肽SPC09、SPC15、SPG01、SPG03、SPG04的免疫抗原,所得免疫血清效价均在1∶1万以上,最高可达1∶51.2万。所建碳二亚胺多肽偶联联合监测法简便实用,可提高多肽抗体制备的成功率。 相似文献
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基于傅里叶变换中红外光谱的小白菜硝酸盐含量的快速测定 总被引:4,自引:0,他引:4
采用不同的中红外光谱(漫反射光谱、光声光谱和衰减全反射光谱),对小白菜叶片中的硝酸盐含量进行快速表征。结果表明,在硝酸盐的特征吸收区(1200~1500 cm-1),3种光谱均存在不同程度的干扰吸收,其中漫反射光谱干扰最多,光声光谱次之,衰减全反射光谱最少;基于红外光谱的主成分回归结果验证了此结果,其线性回归系数(R2)分别为0.4003、0.4874和0.8741。采用衰减全反射光谱并结合偏最小二乘法可进一步改进硝态氮的预测模型,显著减少预测误差,相关系数(R2)为0.8851,RPD值为3.19,预测模型达到很优秀水平。因此,中红外衰减全反射光谱可应用于小白菜叶片中硝酸盐的快速测定。 相似文献
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以B淋巴细胞表面CD20抗原靶向的单克隆抗体Rituximab为载体, 通过共价键偶联荧光基团菁染料Cy7, 获得了新型荧光分子探针Cy7-Rituximab. 利用全光谱紫外-可见分光光度仪、SDS-聚丙烯酰胺凝胶电泳和基质辅助激光解析电离飞行时间质谱等对该探针结构进行表征, 并通过激光共聚焦显微镜观察了其在弥漫大B细胞淋巴瘤(DLBCL)细胞中的摄取情况. 选用BALB/C裸鼠为模型, 尾静脉注射 Cy7-Rituximab, 通过活体荧光成像系统观察了其在小鼠体内的分布情况. 研究结果表明, 修饰后的Cy7-Rituximab保持了原有抗体的免疫活性. 活体荧光成像结果表明, 在CD20高表达的脾脏部位监测到该分子探针的特异性浓集. 相似文献
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三七总皂甙对牛血清白蛋白溶液构象的影响 总被引:25,自引:5,他引:25
应用衰减全反射傅立叶变换红外光谱结合荧光光谱和紫外光谱研究了中药三七 的有效成分三七总皂甙与牛血清白蛋白(BSA)的相互作用,采用对蛋白质红外光 谱酰氨Ⅰ带和酰氨Ⅲ带进行曲线拟合的方法,定量分析了不同浓度三七总皂甙对 BSA二级结构的影响,发现随着三七总皂甙浓度的增加,蛋白分子结构逐渐发生了 由螺旋向折叠的转化。a-螺旋结构减少了3%,β-折叠结构增加了约5%,其它二级 结构没有明显的变化,红外差谱和荧光光谱的结果为药物与蛋白质的作用引起牛血 清白蛋白溶液构象的变化提供了佐证,紫外光谱反映了单体皂甙与蛋白质的结合常 数的差异。 相似文献
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蛋白质因其多样性和功能性,是生物体内一类非常重要的分子.通常蛋白质的表征需要借助荧光或者酶的标记.而纳米孔技术,得益于免标记、单分子检测等优势,为蛋白质的表征提供了新方向.我们使用固态纳米孔完成了单个蛋白质分子及蛋白质-蛋白质结合物的检测.可以发现,外部电压和电解质溶液的酸碱度会直接影响蛋白质分子表面带电量,从而加快或延迟其在孔内的易位时间.抗原、抗体本质上都是蛋白质,两者之间具有高度特异性.通过比较抗体溶液在添加特异性抗原前后的易位事件,实现了单个蛋白质分子和蛋白质-蛋白质结合物的区分.未来,纳米孔技术有望应用于多蛋白质分子的辨识、蛋白质分子相互作用机制等方面的研究. 相似文献
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利用手持技术改进测定乙醇分子结构实验 总被引:1,自引:0,他引:1
利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。 相似文献
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Mustafa R. Ibrahim Zacharia A. Fataftah Paul von Ragu Schleyer Peter D. Stout 《Journal of computational chemistry》1987,8(8):1131-1138
Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases. 相似文献
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由于石化行业的生产需要,其材质的使用具有多样性和广泛性,经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识,根据光谱仪的测试能力及标样的采集,实现了一个或几个元素测量范围的扩展,并对其测量的影响因素进行了研究。 相似文献
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V. I. Bol'shakova L. I. Demenkova É. N. Shmidt V. A. Pentegova 《Chemistry of Natural Compounds》1989,24(6):691-694
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988. 相似文献
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V. I. Bol'shakova L. I. Demenkova É. N. Shmidt V. A. Pentegova 《Chemistry of Natural Compounds》1988,24(6):691-694
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae. 相似文献
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Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin
E. I. Kapinus V. A. Ganzha B. M. Dzhagarov E. I. Sagun V. B. Pavlenko 《Theoretical and Experimental Chemistry》1989,25(2):146-151
The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989. 相似文献
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The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted
indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator
model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was
established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing
analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997. 相似文献