Emma J Walker, Carlin J Hamill, Rory Crean, Michael S Connolly, Annmaree K Warrender, Kirsty L Kraakman, Erica J Prentice, Alistair Steyn-Ross, Moira Steyn-Ross, Christopher R Pudney, Marc W van der Kamp, Louis A Schipper, Adrian J Mulholland, Vickery L Arcus
Many enzymes display non-Arrhenius behavior with curved Arrhenius plots in the absence of denaturation. There has been significant debate about the origin of this behavior and recently the role of the activation heat capacity (Δ C P ⧧ ) has been widely discussed. If enzyme-catalyzed reactions occur with appreciable negative values of Δ C P ⧧ (arising from narrowing of the conformational space along the reaction coordinate), then curved Arrhenius plots are a consequence. To investigate these phenomena in detail, we have collected high precision temperature-rate data over a wide temperature interval for a model glycosidase enzyme MalL, and a series of mutants that change the temperature-dependence of the enzyme-catalyzed rate...
April 5, 2024: ACS Catalysis