RATE THEORIES AND PUZZLES OF HEMEPROTEIN KINETICS
RATE THEORIES AND PUZZLES OF HEMEPROTEIN KINETICS
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DOI：
10.1126/science.4012322
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发表时间：
1985-01-01
期刊：
影响因子：
56.9
通讯作者：
WOLYNES, PG
中科院分区：
文献类型：
--
作者：
FRAUENFELDER, H;WOLYNES, PG
用闪光光解法研究了分子氧和一氧化碳与血红素蛋白如肌红蛋白和血红蛋白的结合。在低于200 K的温度下，从血红素口袋内发生结合，与预期相反，两种配体的速率几乎相等。这一观察结果导致了对缔合反应理论的重新审视，并将摩擦、蛋白质结构和电子跃迁的性质考虑在内。速率系数的限制情况下，大，小摩擦发现与简单的参数，使用特征长度和时间。这些论点表明，过渡态理论以及基于非绝热微扰理论（被称为黄金法则）的计算可能会失败。对于配体结合反应的数据表明，存在的中间状态没有直接观察到迄今为止。一般的考虑也可以适用于其他生物分子过程，如电子传递。
The binding of dioxygen and carbon monoxide to heme proteins such as myoglobin and hemoglobin has been studied with flash photolysis. At temperatures below 200 K, binding occurs from within the heme pocket and, contrary to expectation, with nearly equal rates for both ligands. This observation has led to a reexamination of the theory of the association reaction taking into account friction, protein structure, and the nature of electronic transitions. The rate coefficients for the limiting cases of large and small friction are found with simple arguments that use characteristic lengths and times. The arguments indicate how transition state theory as well as calculations based on nonadiabatic perturbation theory, which is called the Golden Rule, may fail. For ligand-binding reactions the data suggest the existence of intermediate states not directly observed so far. The general considerations may also apply to other biomolecular processes such as electron transport.