Effect of activation energy microheterogeneity on first-order enzyme deactivation

The influence of microheterogeneity on enzyme inactivation kinetics is examined. A continuous normal distribution of the thermal activation energy is assumed, and using this, a simple mathematical model is developed to find the activity-time trajectories for a microheterogeneous enzyme. Using an example, the model is used to show the quantitative effects of microheterogeneity such as increased order and stability observed during an enzyme inactivation. Experimental measurement of the extent of microheterogeneity in an enzyme sample is also discussed.