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Chemical modification of L-asparaginase with N, O-carboxymethyl chitosan and its effects on plasma half-life and other properties 总被引:1,自引:0,他引:1
E.coli L-asparaginase,an antitumor enzyme,was chemically modified with N,O-carboxymethyl chitosan to lower its artigenicity and increase its plasma half-life.The results showed that the modified L-asparaginase has almost the same apparent Km value as that of native enzyme.The modified L-asparaginase also showed a higher protease stability against trypsin and a-chymotrypsin.After being modified,the enzyme exhibited the complete loss of antigenicity towards antiasparaginase serum.In addition,the higher the molecular weight of modifying reagents,the better the effects on reduction of antigenicity.When tested in vivo,the plasma half-life of the modified enzyme (t1/2=40 h) was over 33 times longer than that of the native enzyme (t1/2=1.2 h). 相似文献
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东北红豆杉提取物吸附法脱色的初步探讨 总被引:7,自引:0,他引:7
本文采用8种树脂对东北红豆杉提取物进行脱色研究.结果表明,带碱性基因的树脂吸附能力比较好,其中以PA-C性能最优,在用于纯化紫杉醇的研究中有良好的前景. 相似文献
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N,O-羧甲基壳聚糖修饰对L-天门冬酰胺酶血浆半衰期及其他性质影响 总被引:2,自引:0,他引:2
将具有抗癌作用的L-天门冬酰胺酶用N,O-羧甲基壳聚糖进行化学修饰,以降低酶的抗原性,提高其在体内的半衰期.实验结果表明,修饰酶的表观K_m值与自由酶相差不多,分别为2.6×10~(-4)mol/L和2.2×10~(-4)mol/L(20℃),而抗胰蛋白酶和糜蛋白酶水解能力有很大提高.酶经修饰后抗原性大大降低,且修饰剂分子量越高,降低抗原性的效果越好.自由酶在兔体内的半衰期为1.2h,而修饰酶为40h,提高了33倍. 相似文献
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高分子载体对米曲霉氨基酰化酶的固定化研究 总被引:4,自引:1,他引:4
合成了一系列不同结构的丙烯酸甲酯—二乙烯基苯交联共聚物,并用多乙烯多胺胺解制得了功能基化交联共聚物。研究了交联度、致孔剂用量和不同的功能基化试剂对这些载体固定化氨基酰化酶效果的影响。比较了固定化氨基酰化酶与溶液酶的酶学性质。用这种载体制成固定化酶柱,对N—乙酰—DL—蛋氨酸和N—乙酰—DL—苯丙氨酸进行连续拆分,得到了很好的效果。 相似文献
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Studies on Immobilization of Aminoacylase From Aspergillus Oryzae on Macroporous Carriers 总被引:1,自引:0,他引:1
Synthesized macroporous cross-linked copolymers of methyl acrylate-divinyl benzene (MA-DVB), acrylamide-N,N'-methylenebisacrylamide (AAM-BIS) and their functionalized products were used for immobilization of aminoacylase from Aspergillus oryzae. Effects of the carrier properties on the activity of immobilized aminoacylase were investigated and effects of substrate concentration, pH, phosphate buffer concentration and temperature on the immobilized aminoacylase were compared with those of the soluble aminoacylase. A column of immobilized aminoaoylase was prepared and used for continuous resolution of N-acyl-DL-methionine; the operational stability of immobilized enzyme was also investigated. 相似文献
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用固定化氨基酰化酶拆分DL-对氯苯丙氨酸王道宾,何炳林(南开大学高分子化学研究所,天津300071)L和D型对氯苯丙氨酸在生理学及多肽药物合成中有重要作用,L型光学异构体可抑制5-羟-色胺的形成 ̄[1],将D型氨基酸用于LHRH桔抗类似物的合成中可延... 相似文献
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壳聚糖微球固定化L-天门冬酰胺酶研究 总被引:7,自引:0,他引:7
以反相悬浮交联法合成了壳聚糖微球,并将其应用于固定化L-天门冬酰胺酶。探讨了不同合成条件对成球情况的影响,研究了固定化酶的性质。结果表明,壳聚糖载体可以较好地吸附L-天门冬酰胺酶。固定化酶的活力回收率较高,且稳定性得到提高。 相似文献
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