Constantino Pedro H, Kaznessis Yiannis N
Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, MN 55455, USA.
Chem Eng Sci. 2017 Nov 2;171:139-148. doi: 10.1016/j.ces.2017.05.029. Epub 2017 May 22.
Many chemical reaction networks in biological systems present complex oscillatory dynamics. In systems such as regulatory gene networks, cell cycle, and enzymatic processes, the number of molecules involved is often far from the thermodynamic limit. Although stochastic models based on the probabilistic approach of the Chemical Master Equation (CME) have been proposed, studies in the literature have been limited by the challenges of solving the CME and the lack of computational power to perform large-scale stochastic simulations. In this paper, we show that the infinite set of stationary moment equations describing the stochastic Brusselator and Schnakenberg oscillatory reactions networks can be truncated and solved using maximization of the entropy of the distributions. The results from our numerical experiments compare with the distributions obtained from well-established kinetic Monte Carlo methods and suggest that the accuracy of the prediction increases exponentially with the closure order chosen for the system. We conclude that maximum entropy models can be used as an efficient closure scheme alternative for moment equations to predict the non-equilibrium stationary distributions of stochastic chemical reactions with oscillatory dynamics. This prediction is accomplished without any prior knowledge of the system dynamics and without imposing any biased assumptions on the mathematical relations among species involved.
生物系统中的许多化学反应网络呈现出复杂的振荡动力学。在诸如调控基因网络、细胞周期和酶促过程等系统中,所涉及的分子数量往往远未达到热力学极限。尽管已经提出了基于化学主方程(CME)概率方法的随机模型,但文献中的研究受到求解CME的挑战以及缺乏进行大规模随机模拟的计算能力的限制。在本文中,我们表明,描述随机布鲁塞尔振子和施纳肯贝格振荡反应网络的无穷多个稳态矩方程可以通过分布熵最大化进行截断和求解。我们数值实验的结果与通过成熟的动力学蒙特卡罗方法获得的分布进行了比较,结果表明预测的准确性随着为系统选择的闭合阶数呈指数增长。我们得出结论,最大熵模型可以用作矩方程的一种有效闭合方案替代方法,以预测具有振荡动力学的随机化学反应的非平衡稳态分布。这种预测无需对系统动力学有任何先验知识,也无需对所涉及物种之间的数学关系施加任何有偏假设即可完成。