共查询到20条相似文献,搜索用时 78 毫秒
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聚苯乙烯阴离子交换树脂固定α—淀粉酶的研究(Ⅱ) 总被引:3,自引:0,他引:3
用聚苯乙烯阴离子交换树脂作载体,采用吸附法将a一淀粉酶固定化,研究了固定化条件和固定化酶的性能。固定化条件为:酶浓度10mg/ml,固定化pH6.8,吸附时间16h,吸附温度6℃。固定化酶的pH稳定性、热稳定性、贮存稳定性都有一定的提高。最适作用温度及PH较自由酶为高,Km值为自由酶的1.6倍。同时也进行了固定化酶的操作稳定性研究。 相似文献
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A simplified procedure for enantioselective synthesis of (S)-( )-2-(6′-methoxyl-2-naphthyl)propionic acid ((S)-( )-naproxen), starting from (6-methoxy-α-naphthyl)-1-propanone,with D-mannitol as auxiliary catalyzed by SmCl3 in one-pot is described. The yield is 87.5%(ee value 99%). 相似文献
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不对称催化氢化制备(S)—(+)—萘普生:Ⅰ.不对称催化剂的合成及催化性能 总被引:6,自引:0,他引:6
全过程合成出手性双膦配体2,2’-双(二苯基膦)-6,6’-二甲基联苯,以金属钌为中心原子,制备出几种不对称催化剂。通过考察不对称氢化制备(S)-(+)-萘普生的反应光学收率,研究了催化剂的催化性能,并与联萘型双膦配体催化剂进行了比较。 相似文献
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不对称催化氢化制备(S)-(+)-萘普生1)Ⅱ.不对称氢化反应条件赵培庆宫照阳(中国科学院兰州化学物理研究所羰基合成与选择氧化国家重点实验室兰州730000)关键词萘普生不对称催化氢化反应条件分类号O643.32不对称催化是分子催化研究中的前沿领域之... 相似文献
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新显色剂N—烯丙基—N′—(氨基对苯磺酸钠)硫脲与金(Ⅲ)的显色反应 总被引:13,自引:1,他引:13
介绍了一种用新合成的显色剂N-烯丙基-N′-(氨基对苯磺酸钠)硫脲(ASAT)光度法测定微量金(Ⅲ)的方法。在pH35~55的HAc-NaAc缓冲体系中,该试剂和金(Ⅲ)形成一种稳定的水溶性配合物,其组成为n(Au3+)∶n(ASAT)=1∶2,配合物的最大吸收峰位于2986nm处,表观摩尔吸光系数为114×105L·mol-1·cm-1。Au3+量在72~568μg/L服从比尔定律,相关系数r=09993。将该法应用于金矿石中微量金的测定,获得满意的结果。 相似文献
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本文报道了高、低熔点的RS(O)CH2CH2S(O)R(R=n-C3H7,n-C8H17,C6H5)与钯(Ⅱ)的配合物(PdCl2·L)的合成也性质,并对R=n-C3H7的一对配合物进行了单晶分析,发现高熔点配体为内消旋体,低熔点配体为外消旋体。 相似文献
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聚(丙烯酰胺—丙烯酸)/聚(丙烯酰胺—二甲基二烯丙基氯化铵)聚电解质复… 总被引:7,自引:0,他引:7
通过动态光散射、粘度和透光率测定,研究了聚(丙烯酰胺-丙烯酸)[P(AM-AA)]/聚(丙烯酰胺-二甲基二烯丙基氯化铵)[P(AM-DMDAAC)]聚电解质复合溶液的结构和性能。结果表明,P(AM-AA)与P(AM-DMDAAC)复合比、溶液浓度和氯化钠用量影响溶液中复合物的构象和流体力学半径。P(AM-AA)与P(AM-DMDAAC)分子链间适度的库仑相互作用,可形成均相P(AM-AA)/P(A 相似文献
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The aim of this work was to develop a trypsin-based micro-immobilized enzyme reactor prepared on a monolithic ethylenediamine BIA Separations CIM (convective interaction media) minidisk. The micro-immobilized enzyme reactor (IMER) was integrated in a liquid chromatography system hyphenated to electrospray ionization tandem mass spectrometry to carry out on-line protein digestion and identification. The performance of this IMER was compared with that obtained using a previously developed bioreactor prepared on a conventional CIM ethylenediamine disk and with that of the commercially available Poroszyme immobilized trypsin cartridge. In this work, we showed how different proteins were identified with good recoveries using a digestion time of 10 min only. 相似文献
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Summary A multimembrane enzyme reactor, operating under an electric field, is described. This reactor is based on the concept of isoelectric
traps, by which a pair of membranes, of appropriate pI value, are able to trap the enzyme, the buffering ions (which have
to be amphoteric), the substrate and, if needed, cofactors. Charged reaction products can thus leave the enzyme chamber and
be recovered in other chambers where they are trapped by the same isoelectric mechanism (if amphoteric). The unique advantages
of such reactors are absence of enzyme inhibition by a feed-back mechanism and reaction yields approaching 100%. Examples
of a urease and a trypsin/casein reactor are given.
Presented at the 21st ISC held in Stuttgart, Germany, 15th–20th September, 1996 相似文献
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磁性壳聚糖微球用于酶的固定化研究:Ⅲ磁性壳聚糖微球的活化及其对脲酶的固化研究 总被引:12,自引:0,他引:12
以环氧氯丙烷活化的磁性壳聚糖微球作为载体、对脲酶进行固定化研究,结果表明,在25℃时,活化磁性壳聚糖微球对脲酶的固定化在2h时就达到了最大值,固定化酶和自由酶的最适温度都在65℃左右,自由酶和固定化酶的米氏常数Km值分别为0.042mol/L和0.008mol/L,固定化酶的Km降低了5倍。 相似文献
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This article outlines some of the factors influencing the choice of a suitable reactor for using immobilized biocatalysts.
We have concentrated on biochemical engineering parameters of immobilized biocatalysts, which are important with respect to
their application in industrial processes. 相似文献
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WANGLian-yong LUJing YUYao-ting 《高等学校化学研究》2004,20(6):795-800
Rheumatoid factors (RFs) are the characteristic autoantibodies of rheumatoid arthritis. Recent researches in our laboratory showed that the immobilized single-stranded DNA (ss-DNA) immunoadsorbent can selectively remove RFs from the serum of patients. In the present paper are studied the modification of argininine, tryptophan, lysine residues and carboxyl terminus of IgGRF, which was separated from patients‘ serum, with 1,2-cyclohexanedione(CHD), N-bromosuccinimide(NBS), pyridoxal 5‘-phosphate (PP) and 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) respectively, and their effects on the adsorption capacity of the immobilized ss-DNA immunoadsorbent for IgGRF. After the specific modification, the corresponding adsorption capacities of the adsorbents were changed from 48%, 46%, 44% and 54% to 84%, 14%, 21% and 81%, respectively. These results indicate that the electrostatic or ionic-bonding is essential for the interaction between ss-DNA and IgGRF. 相似文献
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Lee BS Jayathilaka GD Huang JS Decresce D Borgia JA Zhou X Gupta S 《Electrophoresis》2008,29(15):3160-3163
Modification to the original immobilized metal affinity electrophoresis (IMAEP) technique is presented. SDS-PAGE is used instead of native PAGE for improved extraction of phosphoproteins from a mixture of proteins. Protein samples treated with 2% w/v SDS instead of native sample buffer ensure that proteins are negatively charged. These negative charges on the proteins assure that the proteins migrate electrophoretically towards the anode regardless of their pI values and hence pass through the region embedded with the metal ions. Another benefit of treating proteins with SDS is that it unfolds the phosphoproteins exposing the phosphate groups to facilitate the metal-phosphate interactions. Phosphorylated ovalbumin can only be extracted after SDS sample buffer treatment. Data show that there is no detrimental effect upon SDS treatment on the extraction of phosphoproteins from a mixture of proteins. Electrophoretic migration of phosphoproteins ceases upon encounter with metal ions like Al+3, Ti+3, Fe+3, Fe+2, and Mn+2 whereas non-phosphorylated proteins migrate freely. 相似文献
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微胶囊固定化过氧化氢酶 总被引:5,自引:1,他引:5
以乙基纤维素为膜材,用液中干燥法将过氧化氢酶微胶囊化,研究了温度和pH值对酶活性的影响及过氧化氢和尿素对固定化酶的抑制作用,由于乙基纤维素膜的保护,明胶对pH值的缓冲作用及明胶与尿素的反应,明显地扩大了酶对温度和pH值的适应性,降低了酶活性抑制剂的影响。 相似文献