Chemical dynamics of intracellular biomolecules with non‐exponential lifetime distribution

Abstract Biomolecules often exhibit non‐exponential lifetime distributions in living cells. Chemical dynamics of these biomolecules cannot be described by conventional chemical kinetics or chemical master equations. Here, we present an exact model study to investigate the effects of the nonexponential lifetime distribution on the time‐dependent concentration of biomolecules and its steady‐state fluctuations. Our exact model study shows that the mean product number increases more rapidly with time as the randomness of the product lifetime decreases even when the mean product creation time and the mean product lifetime are held fixed. The product number fluctuation decreases with product lifetime fluctuation when the product creation is a multi‐channel reaction process but increases with product lifetime fluctuation when the product creation is a multi‐step reaction process. This work presents a new paradigm of chemical dynamics that accurately describes the time profile and the steady‐state fluctuation of biomolecular concentrations in living cells.