Hidden Conformational States and Strange Temperature Optima in Enzyme Catalysis.

ABSTRACT: The existence of temperature optima in enzyme catalysis that occur before protein melting sets in can be described by different types of kinetic models. Such optima cause distinctly curved Arrhenius plots and have, for example, been observed in several cold-adapted enzymes from psychrophilic species. The two main explanations proposed for this behavior either invoke conformational equilibria with inactive substrate-bound states or postulate differences in heat capacity between the reactant and transition states. Herein, we analyze the implications of the different types of kinetic models in terms of apparent activation enthalpies, entropies, and heat capacities, using the catalytic reaction of a cold-adapted α-amylase as a prototypic example. We show that the behavior of these thermodynami

SUBMITTER: Aqvist J 

PROVIDER: S-EPMC7584337 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature