Albery W J, Knowles J R
Biochemistry. 1976 Dec 14;15(25):5588-600. doi: 10.1021/bi00670a025.
The theory of the isotopic exchange of deuterium and tritium between an enzyme-substrate complex and the solvent is derived for 16 different types of experiment involving measurements of initial velocities and of the isotopic content of the reactants and products as a function of the extent of reaction. It is shown how the data from these experiments can be analyzed to obtain the rate constants for the individual steps and thereby the Gibbs free energies of the intermediates and transition states in the reaction. The effects of isotopic substitution on each intermidiate and transition state are also found and this allows conclusions to be drawn as to the extent to which a proton is in flight in a particular transition state. Neither substrate handling (that is, on-off steps), nor the isotopic exchange with the solvent, is assumed to be rapid.
推导了酶-底物复合物与溶剂之间氘和氚的同位素交换理论，该理论适用于16种不同类型的实验，这些实验涉及测量初始速度以及反应物和产物的同位素含量随反应程度的变化。展示了如何分析这些实验数据以获得各个步骤的速率常数，从而得到反应中中间体和过渡态的吉布斯自由能。还发现了同位素取代对每个中间体和过渡态的影响，这使得能够就质子在特定过渡态中移动的程度得出结论。既不假定底物处理（即开启-关闭步骤）也不假定与溶剂的同位素交换是快速的。
