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IntroductionInthepastdecade ,itwasfoundthattwoaminoacidresidues ,SerandHis ,workastheactivesitesintheser ineprotease .1 3 Inourpreviouswork ,adipeptideseryl histidine (Ser His)wasfoundtohavetheproteinandnu cleosidescleavageactivity .4 7p Nitrophenylacetate (p NPA)w… 相似文献
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JinShengZHAO ZhenYuYANG YiHeZHANG ZhengYuYANG 《中国化学快报》2004,15(11):1361-1364
Cellulose/cellulose acetate membranes were prepared and functionalized by introducingamino group on it, and then immobilized the glucose oxidase (Gox) on the functionalizd membrane.SECM was applied for the detection of enzyme activity immobilized on the membrane.Immobilized biomolecules on such membranes was combined with analysis apparatus and can beused in bioassays. 相似文献
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[La(CCl3COO)3(bipy).H2O]2和Tb(CCl3COO)3(bipy)2.H2O混配配… 总被引:3,自引:1,他引:3
利用不同溶剂合成并测定了希土三氯醋酸盐与α,a'-联吡啶(bipy)不同比例的配合物(I)La:bipy=1:1,[La(CCl3COO)3(bipy).H2O]2和(Ⅱ)Tb:bipy=1:2,Tb(CCl3COO)3(bipy)2.H2O,结构测定表明配合物(I)与(Ⅱ)均为三斜晶系,中心离子La(或Tb)具有配位数为8的畸变四方反棱柱多面体;但是配合物(I)形成具有对称中心的二聚体。 相似文献
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利用水和乙醇混合溶剂合成了稀土三氯醋酸盐与2份1,10-邻菲绕啉(phen)配合物RE(CCl_3COO)_3(phen)_2·nH_2O(RE=Nd,Sm,n=0;RE=Eu,n=2)的单晶.结构测定表明,Nd(CCl_3COO)_3(phen)_2为三斜晶系,每个三氯醋酸盐均以双齿配位,2个phen亦为双齿配位,故配位单元中钕为10配位;Eu(CCl_3COO)_3(phen)_2·2H_2O为单斜晶系,1个三氯醋酸根在外界,2个三氯醋酸根为单齿配位,2个phen为双齿配位,另有2分配位水,故配位单元中Eu为8配位. 相似文献
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Instead of environmentally toxic chromium oxidant, singlet oxygen generated photcchemically was used as environmentally friendly and benign oxidizing agent to accomplish the transformation of pseudodiosgenin diacetate to diosone efficiently in a low toxic and less expensive solvent acetone. Accordingly 16-dehydropregnenolone acetate(16-DPA), an important intermediate for preparation of steroidal drugs, was prepared in good yield (75%) when photoreaction was run in acetone/acetic anhydride/pyridine system. The mild reaction condition as well as simple and environmentally friendly process made the method commercially viable and important for production of 16-DPA in industrial scale. 相似文献
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ZHANG Xiao-Feng HUAND De-Guang CHEN Feng CHEN Chang-Neng LIU Qiu-Tian② 《结构化学》2003,22(5):525-528
1 INTRODUCTION Water oxidation to oxygen gas by photo- synthetic apparatus of green plants and cyano- bacteria is the origin of this gas in the atmosphere. The water oxidation center is a tetranuclear, oxide- bridged manganese cluster with O,N-based peri- pheral ligation by amino acid side-chain group[1, 2]. The binding of aqua to the Mn site may be impor- tant to the oxidation of aqua for producing dioxygen. 1,10-Phenanthroline has been adopted to simulate coordination sphere of manga… 相似文献
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ZHANG Dan JIA Shu-yong WANG Yue YAO Jie WANG Gong-ying 《高等学校化学研究》2007,23(2):173-175
IntroductionDimethyl carbonate(DMC) is known to be a novelbuilding block in organic synthesis. As an environmen-tally benign compound and a unique intermediate,DMC has attracted much attention[1,2]. Among the va-rious methods for synthesizing DMC, the tra… 相似文献
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离子液体1-乙基-3-甲基咪唑醋酸盐([EMIM]Ac)对壳聚糖具有良好的溶解能力。利用新一代旋转流变仪哈克MARS-Ⅲ考察了壳聚糖-[EMIM]Ac溶液的稳态流变和动态流变性能。稳态流变结果表明:当低黏均分子量壳聚糖离子液体溶液的质量分数在3%以下时,溶液呈牛顿性流体特征,高于此质量分数时溶液呈假塑性流体特征;壳聚糖离子液体溶液的黏度、结构黏度指数随着温度升高而降低;在同一质量分数下,溶液黏度随壳聚糖黏均分子量的增大而增加,溶液的恒剪切活化能黏流活化能随着剪切速率的增大而降低。动态流变结果表明:溶液的储能模量和损耗模量随着温度的升高而下降,储能模量与损耗模量存在一个交叉点,该交叉点随着温度升高向高频区移动。 相似文献