论文标题
在化学系统的演化中，动力学不对称性与耗散，这是单酶趋化性的例证
Kinetic asymmetry versus dissipation in the evolution of chemical systems as exemplified by single enzyme chemotaxis
论文作者
论文摘要
单酶趋化性是一种现象，通过该现象，通过该现象通过该酶的非平衡空间分布由催化反应的底物和产物的浓度梯度产生和维持。这些梯度可以通过新陈代谢自然出现，也可以通过实验性地通过多个通道流动或使用具有半透明膜的扩散室进行。已经提出了有关这种现象机制的许多假设。在这里，我们讨论了一种仅基于扩散和化学动力学的机制，并表明动力学不对称性，底物和产物的OFF速率差异以及扩散不对称性，酶的结合和游离形式的扩散率的差异是酶促方向的全部确定。探索这些控制非平衡行为的这些基本对称性有助于区分化学系统从初始状态到稳态的可能机制，以及确定一个系统在暴露于外部能源时的方向转移的原理是基于热力学的，还是基于动力学，在动力学方面，由现在的结果支持了当前论文的结果。我们的结果表明，尽管耗散不可避免伴随着非平衡现象，包括趋化性，但系统并不能发展以最大化耗散，而是获得最大的动力学稳定性。对其他酶形成的梯度的趋化反应提供了形成被称为变质代谢物的松散关联的机制。由于这些梯度引起的有效力的方向很大程度上取决于酶的动力学不对称性，因此可能是非晶状体的，其中一种酶被一种酶吸引到另一种酶，但另一种酶是由一种酶驱除的，一种酶是一种重要的成分。
Single enzyme chemotaxis is a phenomenon by which a non-equilibrium spatial distribution of an enzyme is created and maintained by concentration gradients of the substrate and product of the catalyzed reaction. These gradients can arise either naturally through metabolism, or experimentally, e.g., by flow of materials through several channels or by use of diffusion chambers with semipermeable membranes. Numerous hypotheses regarding the mechanism of this phenomenon have been proposed. Here we discuss a mechanism based solely on diffusion and chemical kinetics and show that kinetic asymmetry, a difference in the off rates for substrate and for product, and diffusion asymmetry, a difference in the diffusivities of the bound and free forms of the enzyme, are the sole determinates of the direction of chemotaxis. Exploration of these fundamental symmetries that govern nonequilibrium behavior helps to distinguish between possible mechanisms for the evolution of a chemical system from initial to the steady state, and whether the principle that determines the direction a system shifts when exposed to an external energy source is based on thermodynamics, or on kinetics, with the latter being supported by the results of the present paper. Our results show that while dissipation ineluctably accompanies non-equilibrium phenomena, including chemotaxis, systems do not evolve to maximize dissipation, but rather to attain greatest kinetic stability. Chemotactic response to the gradients formed by other enzymes provides a mechanism for forming loose associations known as metabolons. Significantly the direction of the effective force due to these gradients depends on the kinetic asymmetry of the enzyme, and so can be non-reciprocal, where one enzyme is attracted to another enzyme, but the other enzyme is repelled by the one, an important ingredient in the behavior of active matter.
