Noise of the signaling molecule as a function of the diffusion coecient. Noise as a function of diffusion coefficient for the set of parameters γ2 (see Figure 2B): stochastic simulations (circles) and analytical expression. Eq. (18), (solid line). By using the decomposition the differences between the computational and the theoretical distributions quantifies the amount of intrinsic noise (squares). As evidenced by the linear regression (blue short-dashed line) the later remains constant and is the main contribution to the total noise only for large diffusion values, > 104 (see text).