在大脑六金酶三元复合体中的葡萄糖结合同位素效应表明,基本状态不稳定性的部分缓解
Brett E Lewis1, Vern L Schramm
1Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA.
Journal of the American Chemical Society
|April 17, 2003
概括
同位素效应揭示了与人类大脑基因酶的葡萄糖结合相互作用. 核酸结合改变了在特定的葡萄糖位置上的酶接触,影响了酶基质相互作用.
科学领域:
- 生物化学 生物化学
- 酶动力学 酶动力学
- 结构生物学是结构生物学.
背景情况:
- 同位素效应为分子相互作用提供了洞察力.
- 六酶 (E.C.2.7.1.1) 在葡萄糖代谢中起着至关重要的作用.
- 了解酶基质结合是药物开发的关键.
研究的目的:
- 为了研究同位素对葡萄糖与人类大脑基纳酶结合的影响.
- 为了比较这些效应与没有β,gamma-CH(2) -ATP类似物.
- 阐明酶基质识别的结构基础.
主要方法:
- 衡量葡萄糖 - 六酶关联的平衡常数.
- 使用同位素标记的葡萄糖 ([1-3H]-, [2-3H]-, [3-3H]-, [4-3H]-, [5-3H]-, [6,6-3H2]-, [2-14C]-, [6-14C]-葡萄糖).
- 结合数据的比较在存在和缺少一个核酸类似物.
主要成果:
- 在葡萄糖位置H1,H5和H6观察到显著的同位素效应.
- 对各种标记的葡萄糖分子的量化同位素效应与基纳酶结合.
- 检测到由核酸存在影响的结合平衡的变化.
结论:
- 核酸结合会诱导赫索金酶的细微形状变化,影响残留物Asn683和Glu742.
- 这些变化影响了与特定的葡萄糖基组 (OH6) 的相互作用.
- 同位素效应在基质结合过程中作为酶活性位点动态的敏感探针.
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