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Assaying Protein Kinase Activity with Radiolabeled ATP
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阿洛斯特活化揭示了ATP基转移酶产物释放的蛋白质质量调节
Benjamin J Read1, John B O Mitchell2, Rafael G da Silva3
1School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews, UK.
Communications chemistry
|April 6, 2024
概括
酶中的重同位素替代影响蛋白质运动,而不是化学. 对于ATP基转移酶,同位素标签影响产品释放率,而不是化学步骤,揭示了对酶动态的质量依赖作用.
科学领域:
- 生物化学 生物化学
- 酶动力学 酶动力学
- 蛋白质动力学 蛋白质动力学
背景情况:
- 酶催化可以受到蛋白质动态和重同位素替代的影响.
- 来自Acinetobacter baumannii的ATP酸化转移酶 (HisGS) 是histidine生物合成中的一个关键酶.
- 通过HisZ进行的Allosteric调节将速度限制步骤从化学转移到产品释放.
研究的目的:
- 研究重同位素替代对HisGS的催化速率的影响.
- 为了确定同位素效应是否与化学步骤或产品释放有关.
- 探索蛋白质质量在全调节酶功能中的作用.
主要方法:
- 用五种不同质量的HisGS的同位素标记.
- 在低温下测量酶动力学.
- 对催化速率的质量依赖效应的分析.
主要成果:
- 对HisGS的同位素标记没有影响非活性反应速率.
- 在低温下,HisZ激活的HisGS的催化速率以质量依赖的方式下降.
- 这些同位素效应与产品释放有关,而不是化学步骤,并且通过破坏酶-产品相互作用来取消.
结论:
- 蛋白质质量会影响控制产品释放的全调节热运动.
- 改变的蛋白质质量可以扰乱化学步骤之外的催化循环.
- 快速的蛋白质运动,而不仅仅是化学步骤,对于酶调节和功能至关重要.
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