English  |  正體中文  |  简体中文  |  全文笔数/总笔数 : 51258/86283 (59%)
造访人次 : 8008459      在线人数 : 86
RC Version 7.0 © Powered By DSPACE, MIT. Enhanced by NTU Library & TKU Library IR team.
搜寻范围 查询小技巧:
  • 您可在西文检索词汇前后加上"双引号",以获取较精准的检索结果
  • 若欲以作者姓名搜寻,建议至进阶搜寻限定作者字段,可获得较完整数据
  • 进阶搜寻


    jsp.display-item.identifier=請使用永久網址來引用或連結此文件: http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/61502


    题名: Adenosylcobalamin-Dependent Glutamate Mutase: Examination of Substrate and Coenzyme Binding in an Engineered Fusion Protein Possessing Simplified Subunit Structure and Kinetic Properties
    作者: Chen, H.P.;Marsh, EN.
    贡献者: 淡江大學化學學系
    日期: 1997-12
    上传时间: 2013-05-31 11:35:03 (UTC+8)
    出版者: Washington, DC: American Chemical Society
    摘要: Glutamate mutase is comprised of two weakly associating subunits; E and S, that combine to form the coenzyme binding site. The active holoenzyme assembles in a kinetically complex process in which both the stoichiometry and apparent Kd for adenosylcobalamin (AdoCbl) are dependent upon the relative concentrations of the two subunits, as is the enzyme's specific activity. To facilitate mechanistic and structural studies on this enzyme we have genetically fused the S subunit to the C-terminus of the E subunit through an 11 amino acid (Gly-Gln)5-Gly linker segment. This protein, GlmES, binds AdoCbl stoichiometrically and neither the affinity for AdoCbl nor the turnover number depends upon protein concentration. The kcat and Km for both substrate and coenzyme, together with the deuterium isotope effects on Vmax and Vmax/Km, have been determined for the GlmES-catalyzed reaction proceeding in both directions. Compared with wild type, the affinity for AdoCbl is unchanged, but for the conversion of L-glutamate to (2S,3S)-3-methylaspartate both kcat and Km for L-glutamate are decreased by about a third and the isotope effects are reduced, suggesting product release to be more rate-limiting. To test hypotheses concerning the activation of the coenzyme, we examined the binding of adenosylcobalamin, methylcobalamin, and cob(II)alamin to the enzyme. Each of these is bound with essentially the same affinity (2 microM), suggesting that, contrary to expectations, interactions between the protein and the adenosyl moiety do not serve to weaken the cobalt-carbon bond in the ground state.
    關聯: Biochemistry 36(48), pp.14939-14945
    DOI: 10.1021/bi971374g
    显示于类别:[化學學系暨研究所] 期刊論文

    文件中的档案:

    档案 描述 大小格式浏览次数
    index.html0KbHTML130检视/开启
    index.html0KbHTML8检视/开启

    在機構典藏中所有的数据项都受到原著作权保护.

    TAIR相关文章

    DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library & TKU Library IR teams. Copyright ©   - 回馈