Here, Δ ‡ is the change in activation heat capacity and Δ ‡ and ΔS ‡ are the activation enthalpy and entropy, respectively, at an arbitrary reference temperature . Thus, MMRT provides a molecular explanation for the observed curvature in Eyring plots in the absence of denaturation, which has been demonstrated for a variety of biocatalytic reactions (see Table for a list). Nonetheless, previous characterizations of rate-temperature relationships of various enzymes via Eyring plots have generally been performed at only one pH value (typically pH 7 in phosphate buffer, Table ), leaving the pH dimension of the reaction space, as well as protonation effects on any of the activation parameters in equations ( ) and ( ), largely unexplored.