A complete volume profile for the reversible binding of camphor to cytochrome P450cam
A complete volume profile for the reversible binding of camphor to cytochrome P450cam
复制标题
樟脑与细胞色素 P450cam 可逆结合的完整体积曲线
DOI：
10.1007/s00775-011-0867-7
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
R. van Eldik
中科院分区：
文献类型：
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作者：
A. Franke;E. Hartmann;I. Schlichting;R. van Eldik
研究了压力对樟脑与细胞色素P450可逆结合动力学和热力学的影响。反应和活化体积的测定使得能够构建樟脑与P450可逆结合的第一个完整的体积曲线。尽管在低和高K浓度下进行的反应的体积分布是相当相似的，并且都显示出从反应物到过渡态的急剧体积增加和从过渡态到产物态的相对较小的体积变化，但过渡态的位置在很大程度上受溶液中K浓度的影响。同样，确定的樟脑的解离的活化体积的影响，K的存在下，这反映了水的容易进入依赖于K浓度的结合P450的活性位点的变化。仔细分析的组件，有助于观察到的体积变化，允许估计的总数量的水分子驱逐到散装溶剂在结合的樟脑P450和随后的自旋过渡。参考文献中报道的其他研究结果进行了讨论，这些研究涉及在各种反应条件下樟脑与P450结合的动力学和热力学。
The effect of pressure on the kinetics and thermodynamics of the reversible binding of camphor to cytochrome P450 was studied as a function of the K concentration. The determination of the reaction and activation volumes enabled the construction of the first complete volume profile for the reversible binding of camphor to P450. Although the volume profiles constructed for the reactions conducted at low and high K concentrations are rather similar, and both show a drastic volume increase on going from the reactant to the transition state and a relatively small volume change on going from the transition to the product state, the position of the transition state is largely affected by the K concentration in solution. Similarly, the activation volume determined for the dissociation of camphor is influenced by the presence of K, which reflects changes in the ease of water entering the active site of camphor-bound P450 that depends on the K concentration. Careful analysis of the components that contribute to the observed volume changes allowed the estimation of the total number of water molecules expelled to the bulk solvent during the binding of camphor to P450 and the subsequent spin transition. The results are discussed in reference to other studies reported in the literature that deal with the kinetics and thermodynamics of the binding of camphor to P450 under various reaction conditions.