论文标题
共价开关超敏的热力学界限
Thermodynamic bounds on ultrasensitivity in covalent switching
论文作者
论文摘要
类似开关的图案是生化网络的基本构件之一。一个可以用作超敏开关的常见基序是由两种作用于底物作用的酶，一个酶，一个酶，另一个酶取消了共价修饰。为了作为开关工作，必须通过连续的能量消耗来使这种共价修改循环从热力学平衡中固定出来。在这里，我们利用线性框架进行时间尺度分离，以在驱动周期的化学电势差方面建立了任何共价修饰开关性能的紧密界限。这些界限适用于任意酶机制，而不仅仅是具有任意利率常数的Michaelis-Menten，从而反映了对共价切换的基本物理限制。
Switch-like motifs are among the basic building blocks of biochemical networks. A common motif that can serve as an ultrasensitive switch consists of two enzymes acting antagonistically on a substrate, one making and the other removing a covalent modification. To work as a switch, such covalent modification cycles must be held out of thermodynamic equilibrium by continuous expenditure of energy. Here, we exploit the linear framework for timescale separation to establish tight bounds on the performance of any covalent-modification switch, in terms of the chemical potential difference driving the cycle. The bounds apply to arbitrary enzyme mechanisms, not just Michaelis-Menten, with arbitrary rate constants, and thereby reflect fundamental physical constraints on covalent switching.
