典型生化网络构建子块中噪声传播的机制

活性细胞的内部过程是一个内在的随机过程，而细胞内分子丰度的波动对细胞的生长和发育会产生重大影响. 对生化网络（包括信号转导网络和代谢网络）的典型构建子块，采用统一的生化反应模式，应用线性噪声逼近理论刻画出噪声传播的一般机制：信号转导网络中存在噪声传播，且噪声强度满足加和规则；代谢网络中没有噪声传播，稳定态处物种分子数的分布相互独立. 这为理解细胞内部过程奠定了理论基础.关键词：噪声传播线性噪声逼近信号转导网络代谢网络

The mechanism of noise propagation in typical building blocks of biochemical reaction networks

Intracellular processes of live organisms, which can be described by sets of biochemical reactions, are inherently stochastic, where the fluctuations in molecule abundance inside the cell play a crucial role in the cellular growth and development. For typical building blocks of biochemical reaction networks （including signal transduction networks and metabolic networks）, this paper first gives a unified formulation and then presents a general mechanism of noise propagation by applying the linear noise approximation theory. The main results show that: there is noise propagation in signaling transduction pathways and the noise intensity satisfies noise sum rule, and there is no noise propagation in metabolic pathways and the distributions of the steady state molecules mutually independent. The analytical results lay a theoretical foundation for understanding the intracellular processes.