排序方式: 共有27条查询结果,搜索用时 218 毫秒
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利用原子转移自由基聚合方法将含C2~C4烷基链的单体化合物分别接枝到皱褶假丝酵母脂肪酶(CRL)表面合成了HEMA-g-CRL、GMA-g-CRL、nPMA-g-CRL和BMA-g-CRL四种聚合物接枝CRL。CD和荧光光谱学分析显示,聚合物接枝导致HEMA-g-CRL、nPMA-g-CRL和BMA-g-CRL分子的α-螺旋和β-折叠含量增加。与此同时,聚合物接枝CRL分子荧光发射光谱也发生了蓝移,意味着其具有更加紧密的分子构象。酶活测定结果进一步显示,聚合物接枝增强CRL酶活227%~278%。随着单体化合物烷基链长增加,聚合物接枝CRL的K m值由0.17 mmol·L-1降至0.09 mmol·L-1。与此同时,聚合物接枝CRL的k cat值则提高至106~182 s-1。BMA-g-CRL的催化效率达到了野生型CRL的3.28倍。这反映出聚合物接枝助力了CRL“盖子”结构开启和CRL活性中心暴露,促进底物的转化。稳定性测试表明,聚合物接枝提升了CRL的热稳定性并拓宽了其pH操作范围。 相似文献
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Two dense pellicular agarose-glass matrices of different sizes and densities, I.e., AG-S and AG-L, have been characterized for their bed expansion behavior, flow hydrodynamics and particle classifications in an expanded bed system. A 26 mm ID column with side ports was used for sampling the liquid-solid suspension during expanded bed operations. Measurements of the collected solid phase at different column positions yielded the particle size and density distribution data. It was found that the composite matrices showed particle size as well as density classifications along the column axis, I.e., both the size and density of each matrix decreased with increasing the axial bed height. Their axial classifications were expressed by a correlation related to both the particle size and density as a function of the dimensionless axial bed height. The correlation was found to fairly describe the solid phase classifications in the expanded bed system. Moreover, it can also be applied to other two commercial solid matrices designed for expanded bed applications. 相似文献
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病毒样颗粒(virus-like particle,VLP)是衣壳粒蛋白(Capsomere,Cap)形成的分子自组装体,在疫苗、基因治疗和药物输送等领域具有广阔应用前景。Cap的构象稳定性是影响VLP自组装的关键因素。因此,通过全原子分子动力学模拟考察溶液条件对Cap稳定性的影响,展示此过程的构象变化,分析溶剂结构等影响因素,确定溶液条件调控Cap稳定性的微观机理。模拟结果表明,在纯水和稳定缓冲液两种溶液中,蛋白质均通过静电相互作用吸引Na+富集于表面,使其和水分子共同形成包裹蛋白质的壳层结构。这是溶液稳定Cap的重要因素。稳定缓冲液中,大量Na+富集于蛋白质表面,并通过静电吸引诱导形成Cl-壳层。多壳层结构能够更好包裹蛋白质使Cap内部氢键作用增强,从而更好稳定Cap。研究结果初步展示溶液条件调控Cap稳定性的微观机理,为VLP自组装过程调控奠定理论基础。 相似文献
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以三聚氯氰为连接臂,采用两步法将疏水配基胆固醇修饰到交联琼脂糖(Sepharose)介质上,构建了胆固醇配基色谱。以溶菌酶(Lys)为模型蛋白,考察了胆固醇配基色谱的复性效果,并研究了流速、上样质量浓度和上样量对色谱复性效果的影响,确定了溶菌酶复性的最佳方法。研究结果表明,当溶菌酶上样量为1.00 mL,介质含0.25 mg溶菌酶时,在0.02 mL/min操作流速下进行吸附-洗脱复性,其最终蛋白收率和活性收率分别为96.3%和91.4%,有效促进了溶菌酶的复性。 相似文献
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从前期开发的具有极高的吸附容量及传质速率的二乙氨乙基葡聚糖接枝离子交换介质中选取FF-D50-DexD100和FF-DexD100为典型代表,利用Cl-、SCN-、SO42-、HPO42-为模型反离子,以牛血清白蛋白(BSA)为模型蛋白,以商品化介质(Q Sepharose FF、Q Sepharose XL、DEAE Sepharose FF)为对照,在离子强度为0.06mol/L下,系统研究反离子对二乙氨乙基葡聚糖接枝介质的蛋白质吸附与洗脱行为的影响。结果表明,二乙氨乙基葡聚糖接枝介质对不同反离子的偏好性存在差异,且该偏好性差异与基团所处位置(接枝链配基或表面配基)无关。同时,介质偏好性弱的反离子会通过促进二乙氨乙基葡聚糖接枝介质的“链传递”效应加快蛋白质的传质速率,从而提高动态吸附容量。因此,在使用二乙氨乙基葡聚糖接枝介质进行蛋白质色谱柱分离过程中,可在吸附操作中使用HPO42-,在洗脱操作中使用SCN-来优化分离效果。 相似文献
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膨胀床应用中的高密度薄壳型琼脂糖凝胶介质、流体力学与固相分布 总被引:1,自引:0,他引:1
Two dense pellicular agarose-glass matrices of different sizes and densities, i.e., AG-S and AG-L, have been characterized for their bed expansion behavior, flow hydrodynamics and particle classifications in an expanded bed system. A 26 mm ID column with side ports was used for sampling the liquid-solid suspension during expanded bed operations. Measurements of the collected solid phase at different column positions yielded the particle size and density distribution data. It was found that the composite matrices showed particle size as well as density classifications along the column axis, i.e., both the size and density of each matrix decreased with increasing the axial bed height. Their axial classifications were expressed by a correlation related to both the particle size and density as a function of the dimensionless axial bed height. The correlation was found to fairly describe the solid phase classifications in the expanded bed system. Moreover, it can also be applied to other two commercial solid matrices designed for expanded bed applications. 相似文献
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蛋白质分子和界面之间的作用在药物输送以及生物分离等领域至关重要。利用分子动力学模拟考察蛋白质分子在界面附近的行为是最近10年研究的热点。在早期的工作中,Wang等发现同电荷离子交换介质可用于辅助蛋白质复性,但其机理不甚明确。在利用分子动力学模拟研究其分子机理时发现,不同静电作用力参数对模拟结果有直接的影响。因此,通过全原子分子动力学模拟考察不同静电参数条件对模拟结果的影响,展示此过程的构象和能量变化,分析了造成结果差异的原因。研究结果揭示了不同静电参数对模拟结果的影响,为进一步研究蛋白质在界面表面的行为奠定了一定的理论基础。 相似文献