Abstract
The presence of microheterogeneity in enzymes is reviewed and its role in enzyme deactivation kinetics is examined. It is shown that discrete state and continuous distribution analysis of microheterogeneity are very similar. Continuous distribution of the thermal deactivation activation energy is assumed. Using a simple first-order deactivation model, the role of the initial shape and spread of this distribution is examined. Symmetrical distributions are seen to have very similar effects on deactivation kinetics. For asymmetrical distributions, skew of the distribution is shown to be an important parameter. The analysis shows that very detailed deactivation data is necessary to distinguish between different distributions of deactivation activation energies in enzymes.
