应用化学

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稀土离子La3+对精氨酸酶的抑制作用

史竞艳1*,王志勇2,刘欲文2,汪存信2   

  1. (1.武汉生物工程学院化学与环境工程系 武汉 430415;2.武汉大学化学与分子科学学院 武汉 430072)
  • 收稿日期:2011-06-07 修回日期:2011-08-16 出版日期:2012-04-10 发布日期:2012-04-10
  • 通讯作者: 史竞艳,讲师; Tel/Fax:027-89641818; E-mail:shijingyan@gmail.com; 研究方向:生物热化学和分子生物学
  • 基金资助:
    湖北省教育厅科研基金(B20094006)武汉市教育局科研基金(2008K016)资助项目

Inhibition of the Arginase Catalyzed Hydrolysis of L-Arginine by La3+

SHI Jingyan1*, WANG Zhiyong2, LIU Yuwen2, WANG Cunxin2   

  1. (1.Department of Chemistry and Environment Engineering,Wuhan Bioengineering Institute,Wuhan 430415,China;
    2.College of Chemistry and Molecular Sciences,Wuhan University,Wuhan 430072,China)
  • Received:2011-06-07 Revised:2011-08-16 Published:2012-04-10 Online:2012-04-10

摘要: 在37 ℃、pH=9.4、40 mmol/L的巴比妥钠-盐酸缓冲体系中,利用微量热法研究了稀土离子镧对牛肝精氨酸酶催化L-精氨酸水解反应的影响。 实验结果表明,镧离子对精氨酸酶催化反应存在着明显的抑制作用,其抑制类型为非竞争性可逆抑制,求得抑制常数K1为2.74×10-4 mol/L。 根据其抑制类型和离子半径,推测镧离子与精氨酸酶的结合位置远离酶的活性中心。

关键词: 精氨酸酶, 镧离子, 非竞争性可逆抑制, 微量热法

Abstract: The inhibitive role of lanthanum ion on the arginase catalyzed hydrolysis of L-arginine was studied by microcalorimetry in a 40 mmol/L sodium barbiturate-hydrochloric acid buffer solution at 37 ℃ and pH of 9.4. The results indicated La3+ has remarkable inhibition effect on the catalytic activity of arginase and the inhibitory type belongs to the reversible noncompetitive inhibition with the inhibition constant of 2.74×10-4 mol/L. On the basis of the inhibition type and ion radius, we suggested that the binding site of La3+ to arginase is far from the active site of arginase.

Key words: arginase, lanthanum ion, reversible non-competitive inhibition, microcalorimetry

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