we explore the implications of molecular charge fluctuations on the kinetics of electrostatically dominated diffusion-controlled association, employing diffusion theory and brownian computer simulations. in general, stochastically fluctuating degrees of freedom that dynamically couple to the diffusional transport can yield additional dissipative forces, i.e., friction, resonant response or feedback mechanisms. using a minimalistc model we present how charge fluctuations due to randomly fluctuating protonation of a charged ligand influence the association kinetics to a charged membrane. here, the exploration of the limiting and intermediate frequency domains of the fluctuations serve to clarify the use of concepts of an average charge, an average potential, and an associated capacitance for quantitative rate prediction.