Whitehead Medical Research Institute and Department of Physiology, Duke University Medical Center, Durham, North Carolina 27710.
Proc Natl Acad Sci U S A. 1981 Jan;78(1):270-3. doi: 10.1073/pnas.78.1.270.
The chemical potential (mu(L,b)) of a ligand L bound to a protein or enzyme can be rigorously defined, and this paper describes some of its properties in relation to other thermodynamic parameters, with emphasis on thermodynamic parameters that may be used in the elucidation of the mechanism of biological free energy transduction. Free energy transduction involves the transfer of free energy from one molecule to another, and the actual transfer may often occur while both molecules are bound to the transducer enzyme, which means that mu(L,b) for one bound ligand increases at the expense of mu(L,b) for the other. The free energy change for the overall reaction may be very small, and it is not possible to express the phenomenon of transfer, in thermodynamic terms, without the explicit use of mu(L,b) as a parameter.
配体 L 与蛋白质或酶结合的化学势 (μ(L,b)) 可以严格定义,本文描述了其与其他热力学参数的一些关系,重点介绍了可能用于阐明生物自由能转导机制的热力学参数。自由能转导涉及自由能从一个分子转移到另一个分子,而实际转移通常可能发生在两个分子都与转导酶结合时,这意味着一个结合配体的 μ(L,b) 的增加是以牺牲另一个配体的 μ(L,b) 为代价的。整个反应的自由能变化可能很小,如果不明确使用 μ(L,b) 作为参数,就不可能用热力学术语来表达转移现象。