Single-molecule enzymology: stochastic Michaelis-Menten kinetics.

We provide a stochastic analysis of single-molecule enzymatic reactions that follow Michaelis-Menten kinetics. We show that this system can exhibit oscillatory behavior in the non-equilibrium steady-state at appropriate substrate concentrations. The stochastic model includes both enzyme dynamics and substrate turnover kinetics. The relationship between the probability of substrate survival and the time-correlation of enzyme conformation trajectories is discussed. Deterministic kinetics at large substrate concentrations are obtained as a limit of the stochastic model. We suggest that in addition to fluctuating enzyme conformation, the stochastic nature of substrate concentration fluctuations is another possible source of the complex behavior of single-molecule enzyme kinetics. Copyright 2002 Elsevier Science B.V.