文章摘要
李飞 李忠培 占志 王冬雪 朱美财.抗PAI 抑制作用的纤溶酶原激活剂突变体的活性研究[J].,2014,14(16):3029-3032
抗PAI 抑制作用的纤溶酶原激活剂突变体的活性研究
Expression and Activity of Tissue-type Plasminogen Activator MutantReteplase with Deletion of PAI-1 Binding Sites
  
DOI:
中文关键词: 组织型纤溶酶原激活剂  突变体  蛋白表达  纯化  酶动力学
英文关键词: t-PA  Mutant  Protein expression  Purification  Enzyme kinetics
基金项目:国家“重大新药创制”科技重大专项(2009 ZX09103-603)
作者单位
李飞 李忠培 占志 王冬雪 朱美财 中国人民解放军空军总医院临床检验中心
泰安市中心医院检验科 
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中文摘要:
      目的:重组表达抗PAI 抑制作用的t-PA 突变体,经诱导表达、复性、纯化后进行生物学活性和酶动力学分析。方法:构建 pBV220-tpa 重组表达质粒,经DNA测序确认后,转化至大肠杆菌DH5a,温控诱导表达,凝胶过滤法对包涵体蛋白进行初步纯化, 复性后,过刺桐胰蛋白酶亲和层析柱纯化,酶动力学分析其活性。结果:测序证实,t-PA突变体的DNA序列正确,表达蛋白占总菌 体蛋白的30%,经纯化后纯度达90%以上,比活性为7.0× 108IU/mg,t-PA 突变体与PAI-1 反应后,其活性未受到抑制。t-PA 突变 体酶的米氏常数Km为0.5298,最大水解速度Vmax为0.0595。结论:经生物学活性测定, 表达蛋白能够明显抵抗PAI 的抑制作用, 并具有良好的生物活性,该突变体有可能成为用量更少、疗效更佳的新型溶栓药物。
英文摘要:
      Objective: To construct a prokaryotic expression vector for tissue-type plasminogen activator mutantreteplase with deletion of a PAI-1 binding site, and valuate its biological activity by enzyme kinetics analysis.Methods:The recombinant plasmid pBV220-t-PA was transformed into E.coli for expression after DNA sequencing. The recombinant mutant t-PA inclusion body was purified with gel filtration, and then was purified with erythrina trypsin affinity chromatography after refolding.Results:The mutant t-PA encoding sequence was confirmed by DNA sequencing. The expression product was about 30% of whole lysis protein. After purified with gel filtration, the protein purity was more than 95%. The specific activity of mutant t-PA with deletion of PAI-1 binding site was 4.2× 105 IU/mg. This protein was not inhibited by PAI-1. The Kmwas 0.3298 umol·L-1 and Vmax of mutant t-PA was 0.0476 umol·min-1· g-1.Conclusion:Recombinant mutant t-PA with deletion of PAI-1 binding site prepared from E.coli could resist the inhibitions of PAI-1, and harbor a better biological activity.
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