Fluctuating reaction rate and non-exponential blinking statistics in single-enzyme kinetics

Extending the Michaelis–Menten kinetic scheme, we consider a three-state diffusion-controlled reaction model to investigate the effects of fluctuating reaction rate on the blinking statistics of single-enzyme catalytic reactions. As a result of conformational changes, the barrier-height and the reaction rate for the bottleneck enzymatic reaction could fluctuate in time, leading to non-exponential blinking statistics. To illustrate model applications, some reported experimental data for single β-galactosidase molecules were reanalyzed here to extract useful kinetic parameters.