活性中心

However, if one alkylation center is blocked, the carcinogenic potency of the compounds is decreased obviously.

但如果有一个烷化中心丧失活性，就会明显减弱化合物的致癌活性。

The 20S catalytic core of the 26S proteasome has the shape of a barrel made of four rings which are composed of seven differentαsubunitsα_1-α_7 at two outer rings and seven differentβsubunitsβ_1-β_7 at two inner rings at which the catalytic sites locate. Three of theβsubunits contain proteolyses sites, which are sequestered in the hollow interior of the 20S particle. Substrates enter the 20S through a narrow channel formed by theβsubunits, whose N-termini, depending on their conformation, can either obstruct or allow substrate entry and thus function as a gate. This entry channel is narrow and only permits passage of unfolded, linearized polypeptides.

哺乳动物26S蛋白酶体是由一个20S催化颗粒(catalytic particle，CP)和两个19S调节颗粒(regulatory particle，RP)组成的ATP(adenosine-triphosphate，ATP)依赖性蛋白水解酶复合体。20S CP是26S蛋白酶体的催化核心，它是由4个圆环堆叠形成的桶状复合物，其中两侧外环每个环是由α_1-α_7亚基组成，两个内环每个环是由β_1-β_7亚基组成，4个环的中央形成一个狭窄的内腔。2个β内环形成了20S CP的催化中心空腔，其内壁为催化活性位点所在地；外侧α环中心的孔道是底物到达催化中心空腔的通道，一般被α亚基上的N末端所封闭，阻止胞内非目的靶蛋白进入20S CP内被降解破坏。

The results showed that: 1 reinders' redox buffers were used to study the redox properties not only for latent image centers but also for sensitivity centers; 2 The redox potential of Ag2S sensitivity centers was less negative than －220 mV with respect to the saturated calomel electrode in our experiment and the redox potential of latent image centers was between －220 mV and －190 mV; 3 The redox activities of latent image centers were much higher than that of sensitivity centers.

实验结果表明：1Reinders的氧化还原缓冲液的方法，不仅可用于研究潜影中心，也可用于研究敏化中心；2本实验条件下的硫化银敏化中心的氧化还原电位约略负于－220 mV，潜影中心的氧化还原电位值是介于－220 mV与－190 mV之间；3潜影中心的氧化还原活性较敏化中心大得多。

The optically active defect centers of such types as E', two kinds of oxygen-deficiency and some kinds of oxygen-richness in silica play an important role in optical communication fiber and UV absorption. The researches on some oxygen-deficient defects and the metal ions doped or implanted semiconductor nanoparticles with fine luminescence properties have made it possible for silica to be used in the lighting field.

氧化硅材料本征E'、2种缺氧型以及各种富氧型光活性缺陷中心在光导纤维及紫外吸收等应用中扮演了很重要的作用，某些具有良好发光性能的缺氧中心及掺杂离子或半导体纳米粒子发光中心的深入研究使氧化硅材料在照明领域具有良好的应用前景。

The transformation of the active and inactive PS Ⅱ centers in the readaptation period under room temperaturre after heat stress is studied.

高温胁迫后的室温恢复期中有活性和无活性PS Ⅱ中心相互转化的研究。

The results showed that hydrogen peroxide, silanols species and TiO〓 didn't have solvolysis activity of propylene oxide. While framework Al, coordinatively unsaturated Ti〓 ions as Lewis acid sites in the framework, Ti-OH and the five member ring active titanium species formed by TS-1, hydrogen peroxide and solvent can catalyze the solvolysis of propylene oxide.

研究结果表明：原料双氧水和TS-1沸石上的SiOH和TiO〓对环氧丙烷溶剂解反应无催化活性；而下列物种对环氧丙烷溶剂解反应具有催化活性：TS-1中的骨架铝，沸石骨架中配位不饱和的Ti〓形成的L酸中心，TS-1水解产生的钛羟基和由TS-1，双氧水和溶剂相互作用所生成的五元环中间活性钛物种。

The apparent quantum efficiency of SO〓〓/TiO〓 was 10 times of that of TiO〓 catalyst for the photocatalytic degradation of bromomethane. Therefore, the SO〓〓/TiO〓 superacid catalyst is promising for practical application in environmental remediation.It was found that both L and B acid sites exist on SO〓〓/TiO〓 photocatalyst while only L acid sites on TiO〓 photocatalyst. On the basis of experimental results, the synergistic model of superacidic centers was proposed for SO〓〓/TiO〓 photocatalyst to explain the photocatalytic behavior and the mechanism of superacidifing effects, assuming that the adjacent L and B acid sites induced by SO〓〓 comprise cooperatively the superacidic center on superacid photocatalyst. The group cooperation of the superacidic center could strengthen the surface acidity, increase surface acid sites and the adsorbtion of O〓, promote separation of photogenerated electron-hole pair, enhance the interfacial transfer of charges and reversibility of water adsorption. Consequently the excellent photocatalytic activity, reaction stability and resistibility to humidity of SO〓〓/TiO〓 superacid photocatalyst may attributed to the group cooperated effect of the superacidic center on the photocatalyst.

研究结果表明：SO〓〓与TiO〓表面的结合为螯合式双配位结构；TiO〓光催化剂表面经H〓SO〓浸渍处理后，提高了表面酸性，改善了催化剂结构和光催化性能，当H〓SO〓浸渍浓度为1.0mol.L〓、烧结温度为450℃时，可制得SO〓〓/TiO〓超强酸催化剂(H〓＜-12.14)，其结构和光催化活性得到明显改善，与TiO〓相比，SO〓〓/TiO〓光催化剂的锐钛矿含量高、晶粒小、BET比表面积大、孔径分布集中、光谱吸收边蓝移，具有优异的光催化氧化活性、稳定性及抗湿性能，光催化降解溴代甲烷的表观量子效率比TiO〓催化剂提高了一个数量级，是一种有实际应用前景的高效光催化剂；由此提出了SO〓〓/TiO〓超强酸催化剂表面集团协同作用的超强酸中心模型，认为在SO〓〓/TiO〓超强酸催化剂表面，由SO〓〓诱导的相邻L酸中心和B酸中心组成了集团协同作用的超强酸中心，其集团协同作用显著地增强了催化剂表面酸性、增大了表面酸量及O〓吸附量、促进了光生电子和空穴的分离及界面电荷转移，具有可逆吸附水的性能，是SO〓〓/TiO〓超强酸催化剂具有优异的光催化氧化活性、很好的活性稳定性及抗湿性能的重要原因。

So this kind of compounds is a research focus in herbicide discovery and development. Based on the photosynthesis center D1 protein structure model of high plant Pisum Sativum, we rationally designed and modified the branch chains of cyanoacrylates in order to improve their herbicidal activity.

本论文根据已建立的高等植物豌豆光合作用中心D1蛋白模型结构和前期工作经验，运用生物合理设计方法，对其中抑制希尔反应活性最好的一类化合物—氰基丙烯酸酯类除草剂的若干侧链进行修饰，以期得到抑制活性较好的化合物。

In this research work, from a large amount of endophytes which had been screened based on several models, dozens of strains showed activities. One of which were taxonomically identified, and their secondary metabolites were studied.

本论文利用上海来益生物药物研发中心的植物内生菌资源，通过各种模型的筛选，在获得活性菌株的基础上，对其中的一株进行了菌种鉴定，并对它们的次级代谢产物进行分离、纯化及活性初步研究。

First, the significant of co-factor InsP6 and center water in the mechanism of auxins are explored by docking; second, the experiments that compared with the docking rusults of two situations involving fully rigid and selective flexible of active residue of the receptor TIR1 illuminate that selective flexibility docking by AutoDock4 reports more rational results, so that, AutoDock4 dockings are implemented with TIR1-Auxins; third, AutoDock4 docking by TIR1-Auxins-Aux/IAA illuminates that auxin as a molecular glue enhances the interaction between TIR1 receptor and Aux/IAA substrate by the weak interactions, such as hydrogen bond and hydrophobic interaction, furthermore, the weak interactions between receptor protein and ligands greatly influence on auxin activity of auxin ligands.

首先， 通过分子对接计算研究辅酶InsP6以及中心水分子在生长素反应中的重要作用；其次，比较受体大分子完全刚性以及活性残基部分柔性的两种情况下的分子对接结果，说明AutoDock4实现了受体分子活性残基的部分柔性而使对接结果更加合理，进而使用AutoDock4方法对TIR1-Auxins体系进行对接计算；最后，对TIR1-Auxins-Aux/IAA体系进行分子对接计算，结果表明，生长素配体分子作为&分子胶水&直接与受体大分子TIR1以及底物多肽Aux/IAA形成强的弱相互作用，如氢键作用、疏水相互作用，促进了受体TIR1与Aux/IAA底物之间的结合，进而说明氢键作用和疏水相互作用等弱相互作用对于生长素分子的活性具有很大的影响。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。